diff --git a/icinga-app/icinga.cpp b/icinga-app/icinga.cpp
index acae5d544..0c6d058b0 100644
--- a/icinga-app/icinga.cpp
+++ b/icinga-app/icinga.cpp
@@ -192,9 +192,8 @@ int Main(void)
 		CLICommand::ParseCommand(argc, argv, visibleDesc, hiddenDesc, positionalDesc,
 		    vm, cmdname, command, autocomplete);
 	} catch (const std::exception& ex) {
-		std::ostringstream msgbuf;
-		msgbuf << "Error while parsing command-line options: " << ex.what();
-		Log(LogCritical, "icinga-app", msgbuf.str());
+		Log(LogCritical, "icinga-app")
+		    << "Error while parsing command-line options: " << ex.what();
 		return EXIT_FAILURE;
 	}
 
@@ -337,30 +336,26 @@ int Main(void)
 	
 		if (!gr) {
 			if (errno == 0) {
-				std::ostringstream msgbuf;
-				msgbuf << "Invalid group specified: " + group;
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "Invalid group specified: " << group;
 				return EXIT_FAILURE;
 			} else {
-				std::ostringstream msgbuf;
-				msgbuf << "getgrnam() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "getgrnam() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 				return EXIT_FAILURE;
 			}
 		}
 	
 		if (getgid() != gr->gr_gid) {
 			if (!vm.count("reload-internal") && setgroups(0, NULL) < 0) {
-				std::ostringstream msgbuf;
-				msgbuf << "setgroups() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "setgroups() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 				return EXIT_FAILURE;
 			}
 	
 			if (setgid(gr->gr_gid) < 0) {
-				std::ostringstream msgbuf;
-				msgbuf << "setgid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "setgid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 				return EXIT_FAILURE;
 			}
 		}
@@ -372,14 +367,12 @@ int Main(void)
 	
 		if (!pw) {
 			if (errno == 0) {
-				std::ostringstream msgbuf;
-				msgbuf << "Invalid user specified: " + user;
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "Invalid user specified: " << user;
 				return EXIT_FAILURE;
 			} else {
-				std::ostringstream msgbuf;
-				msgbuf << "getpwnam() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "getpwnam() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 				return EXIT_FAILURE;
 			}
 		}
@@ -387,16 +380,14 @@ int Main(void)
 		// also activate the additional groups the configured user is member of
 		if (getuid() != pw->pw_uid) {
 			if (!vm.count("reload-internal") && initgroups(user.CStr(), pw->pw_gid) < 0) {
-				std::ostringstream msgbuf;
-				msgbuf << "initgroups() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "initgroups() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 				return EXIT_FAILURE;
 			}
 	
 			if (setuid(pw->pw_uid) < 0) {
-				std::ostringstream msgbuf;
-				msgbuf << "setuid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-				Log(LogCritical, "cli",  msgbuf.str());
+				Log(LogCritical, "cli")
+				    << "setuid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 				return EXIT_FAILURE;
 			}
 		}
diff --git a/lib/base/application.cpp b/lib/base/application.cpp
index acb6d751a..772a71e40 100644
--- a/lib/base/application.cpp
+++ b/lib/base/application.cpp
@@ -286,11 +286,10 @@ mainloop:
 
 		if (abs(timeDiff) > 15) {
 			/* We made a significant jump in time. */
-			std::ostringstream msgbuf;
-			msgbuf << "We jumped "
-				<< (timeDiff < 0 ? "forward" : "backward")
-				<< " in time: " << abs(timeDiff) << " seconds";
-			Log(LogInformation, "Application", msgbuf.str());
+			Log(LogInformation, "Application")
+			    << "We jumped "
+			    << (timeDiff < 0 ? "forward" : "backward")
+			    << " in time: " << abs(timeDiff) << " seconds";
 
 			Timer::AdjustTimers(-timeDiff);
 		}
@@ -682,7 +681,8 @@ int Application::Run(void)
 	try {
 		UpdatePidFile(GetPidPath());
 	} catch (const std::exception&) {
-		Log(LogCritical, "Application", "Cannot update PID file '" + GetPidPath() + "'. Aborting.");
+		Log(LogCritical, "Application")
+		    << "Cannot update PID file '" << GetPidPath() << "'. Aborting.";
 		return false;
 	}
 
@@ -714,7 +714,8 @@ void Application::UpdatePidFile(const String& filename, pid_t pid)
 		m_PidFile = fopen(filename.CStr(), "w");
 
 	if (m_PidFile == NULL) {
-		Log(LogCritical, "Application", "Could not open PID file '" + filename + "'.");
+		Log(LogCritical, "Application")
+		    << "Could not open PID file '" << filename << "'.";
 		BOOST_THROW_EXCEPTION(std::runtime_error("Could not open PID file '" + filename + "'"));
 	}
 
@@ -737,9 +738,8 @@ void Application::UpdatePidFile(const String& filename, pid_t pid)
 	}
 
 	if (ftruncate(fd, 0) < 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "ftruncate() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Application",  msgbuf.str());
+		Log(LogCritical, "Application")
+		    << "ftruncate() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(posix_error()
 		    << boost::errinfo_api_function("ftruncate")
diff --git a/lib/base/dynamicobject.cpp b/lib/base/dynamicobject.cpp
index 7a41cdfde..919ee0599 100644
--- a/lib/base/dynamicobject.cpp
+++ b/lib/base/dynamicobject.cpp
@@ -239,7 +239,8 @@ Value DynamicObject::InvokeMethod(const String& method,
 
 void DynamicObject::DumpObjects(const String& filename, int attributeTypes)
 {
-	Log(LogInformation, "DynamicObject", "Dumping program state to file '" + filename + "'");
+	Log(LogInformation, "DynamicObject")
+	    << "Dumping program state to file '" << filename << "'";
 
 	String tempFilename = filename + ".tmp";
 
@@ -307,7 +308,8 @@ void DynamicObject::RestoreObject(const String& message, int attributeTypes)
 
 	ASSERT(!object->IsActive());
 #ifdef _DEBUG
-	Log(LogDebug, "DynamicObject", "Restoring object '" + name + "' of type '" + type + "'.");
+	Log(LogDebug, "DynamicObject")
+	    << "Restoring object '" << name << "' of type '" << type << "'.";
 #endif /* _DEBUG */
 	Dictionary::Ptr update = persistentObject->Get("update");
 	Deserialize(object, update, false, attributeTypes);
@@ -316,7 +318,8 @@ void DynamicObject::RestoreObject(const String& message, int attributeTypes)
 
 void DynamicObject::RestoreObjects(const String& filename, int attributeTypes)
 {
-	Log(LogInformation, "DynamicObject", "Restoring program state from file '" + filename + "'");
+	Log(LogInformation, "DynamicObject")
+	    << "Restoring program state from file '" << filename << "'";
 
 	std::fstream fp;
 	fp.open(filename.CStr(), std::ios_base::in);
@@ -337,9 +340,8 @@ void DynamicObject::RestoreObjects(const String& filename, int attributeTypes)
 
 	upq.Join();
 
-	std::ostringstream msgbuf;
-	msgbuf << "Restored " << restored << " objects";
-	Log(LogInformation, "DynamicObject", msgbuf.str());
+	Log(LogInformation, "DynamicObject")
+	    << "Restored " << restored << " objects";
 }
 
 void DynamicObject::StopObjects(void)
diff --git a/lib/base/logger.cpp b/lib/base/logger.cpp
index 205103199..2cee05d8b 100644
--- a/lib/base/logger.cpp
+++ b/lib/base/logger.cpp
@@ -77,7 +77,7 @@ std::set<Logger::Ptr> Logger::GetLoggers(void)
  * @param facility The log facility.
  * @param message The message.
  */
-void icinga::Log(LogSeverity severity, const String& facility,
+void icinga::IcingaLog(LogSeverity severity, const String& facility,
     const String& message)
 {
 	LogEntry entry;
diff --git a/lib/base/logger.hpp b/lib/base/logger.hpp
index d8b0bc162..61ecc5050 100644
--- a/lib/base/logger.hpp
+++ b/lib/base/logger.hpp
@@ -23,6 +23,7 @@
 #include "base/i2-base.hpp"
 #include "base/logger.thpp"
 #include <set>
+#include <sstream>
 
 namespace icinga
 {
@@ -102,6 +103,39 @@ private:
 	    const String& message);
 };
 
+I2_BASE_API void IcingaLog(LogSeverity severity, const String& facility, const String& message);
+
+class Log
+{
+public:
+	inline Log(LogSeverity severity, const String& facility, const String& message)
+		: m_Severity(severity), m_Facility(facility)
+	{
+		m_Buffer << message;
+	}
+
+	inline Log(LogSeverity severity, const String& facility)
+		: m_Severity(severity), m_Facility(facility)
+	{ }
+
+	inline ~Log(void)
+	{
+		IcingaLog(m_Severity, m_Facility, m_Buffer.str());
+	}
+
+	template<typename T>
+	Log& operator<<(const T& val)
+	{
+		m_Buffer << val;
+		return *this;
+	}
+
+private:
+	LogSeverity m_Severity;
+	String m_Facility;
+	std::ostringstream m_Buffer;
+};
+
 }
 
 #endif /* LOGGER_H */
diff --git a/lib/base/process.cpp b/lib/base/process.cpp
index 39630e824..5d368f4a7 100644
--- a/lib/base/process.cpp
+++ b/lib/base/process.cpp
@@ -437,8 +437,8 @@ void Process::Run(const boost::function<void(const ProcessResult&)>& callback)
 	m_FD = outReadPipe;
 	m_PID = pi.dwProcessId;
 
-	Log(LogNotice, "Process", "Running command " + PrettyPrintArguments(m_Arguments) +
-	    ": PID " + Convert::ToString(m_PID));
+	Log(LogNotice, "Process")
+	    << "Running command " << PrettyPrintArguments(m_Arguments) << ": PID " << m_PID;
 
 #else /* _WIN32 */
 	int fds[2];
@@ -549,8 +549,8 @@ void Process::Run(const boost::function<void(const ProcessResult&)>& callback)
 
 	m_PID = m_Process;
 
-	Log(LogNotice, "Process", "Running command " + PrettyPrintArguments(m_Arguments) +
-	    ": PID " + Convert::ToString(m_PID));
+	Log(LogNotice, "Process")
+	    << "Running command " << PrettyPrintArguments(m_Arguments) <<": PID " << m_PID;
 
 	// free arguments
 	for (int i = 0; argv[i] != NULL; i++)
@@ -599,9 +599,9 @@ bool Process::DoEvents(void)
 		double timeout = m_Result.ExecutionStart + m_Timeout;
 
 		if (timeout < Utility::GetTime()) {
-			Log(LogWarning, "Process", "Killing process " + Convert::ToString(m_PID) +
-			    " (" + PrettyPrintArguments(m_Arguments) + ") after timeout of " +
-			    Convert::ToString(m_Timeout) + " seconds");
+			Log(LogWarning, "Process")
+			    << "Killing process " << m_PID << " (" << PrettyPrintArguments(m_Arguments)
+			    << ") after timeout of " << m_Timeout << " seconds";
 
 			m_OutputStream << "<Timeout exceeded.>";
 #ifdef _WIN32
@@ -649,9 +649,8 @@ bool Process::DoEvents(void)
 	DWORD exitcode;
 	GetExitCodeProcess(m_Process, &exitcode);
 
-	Log(LogNotice, "Process", "PID " + Convert::ToString(m_PID) +
-	    " (" + PrettyPrintArguments(m_Arguments) + ") terminated with exit code " +
-	    Convert::ToString(exitcode));
+	Log(LogNotice, "Process")
+	    << "PID " << m_PID << " (" << PrettyPrintArguments(m_Arguments) << ") terminated with exit code " << exitcode;
 #else /* _WIN32 */
 	int status, exitcode;
 	if (waitpid(m_Process, &status, 0) != m_Process) {
@@ -663,12 +662,11 @@ bool Process::DoEvents(void)
 	if (WIFEXITED(status)) {
 		exitcode = WEXITSTATUS(status);
 
-		Log(LogNotice, "Process", "PID " + Convert::ToString(m_PID) +
-		    " (" + PrettyPrintArguments(m_Arguments) + ") terminated with exit code " +
-		    Convert::ToString(exitcode));
+		Log(LogNotice, "Process")
+		    << "PID " << m_PID << " (" << PrettyPrintArguments(m_Arguments) << ") terminated with exit code " << exitcode;
 	} else if (WIFSIGNALED(status)) {
-		Log(LogWarning, "Process", "PID " + Convert::ToString(m_PID) + " was terminated by signal " +
-		    Convert::ToString(WTERMSIG(status)));
+		Log(LogWarning, "Process")
+		    << "PID " << m_PID << " was terminated by signal " << WTERMSIG(status);
 
 		std::ostringstream outputbuf;
 		outputbuf << "<Terminated by signal " << WTERMSIG(status) << ".>";
diff --git a/lib/base/socket.cpp b/lib/base/socket.cpp
index 562ddd9bf..a82a028bb 100644
--- a/lib/base/socket.cpp
+++ b/lib/base/socket.cpp
@@ -131,17 +131,15 @@ String Socket::GetAddressFromSockaddr(sockaddr *address, socklen_t len)
 	if (getnameinfo(address, len, host, sizeof(host), service,
 	    sizeof(service), NI_NUMERICHOST | NI_NUMERICSERV) < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "getnameinfo() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "getnameinfo() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getnameinfo")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "getnameinfo() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "getnameinfo() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getnameinfo")
@@ -168,17 +166,15 @@ String Socket::GetClientAddress(void)
 
 	if (getsockname(GetFD(), (sockaddr *)&sin, &len) < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "getsockname() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "getsockname() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getsockname")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "getsockname() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "getsockname() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getsockname")
@@ -210,17 +206,15 @@ String Socket::GetPeerAddress(void)
 
 	if (getpeername(GetFD(), (sockaddr *)&sin, &len) < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "getpeername() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "getpeername() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getpeername")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "getpeername() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "getpeername() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getpeername")
@@ -245,17 +239,15 @@ void Socket::Listen(void)
 {
 	if (listen(GetFD(), SOMAXCONN) < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "listen() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "listen() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("listen")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "listen() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "listen() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("listen")
@@ -273,17 +265,15 @@ size_t Socket::Write(const void *buffer, size_t count)
 
 	if (rc < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "send() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "send() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("send")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "send() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "send() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("send")
@@ -303,17 +293,15 @@ size_t Socket::Read(void *buffer, size_t count)
 
 	if (rc < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "recv() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "recv() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("recv")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "recv() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "recv() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("recv")
@@ -337,17 +325,15 @@ Socket::Ptr Socket::Accept(void)
 
 	if (fd < 0) {
 #ifndef _WIN32
-		std::ostringstream msgbuf;
-		msgbuf << "accept() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "accept() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("accept")
 		    << boost::errinfo_errno(errno));
 #else /* _WIN32 */
-		std::ostringstream msgbuf;
-		msgbuf << "accept() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "accept() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("accept")
@@ -379,9 +365,8 @@ bool Socket::Poll(bool read, bool write)
 	rc = select(GetFD() + 1, &readfds, &writefds, &exceptfds, NULL);
 
 	if (rc < 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "select() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "select() failed with error code " << WSAGetLastError() << ", \"" << Utility::FormatErrorNumber(WSAGetLastError()) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("select")
@@ -396,9 +381,8 @@ bool Socket::Poll(bool read, bool write)
 	rc = poll(&pfd, 1, -1);
 
 	if (rc < 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "poll() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "Socket",  msgbuf.str());
+		Log(LogCritical, "Socket")
+		    << "poll() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("poll")
diff --git a/lib/base/tcpsocket.cpp b/lib/base/tcpsocket.cpp
index 5bdcd991b..b3bfbe52a 100644
--- a/lib/base/tcpsocket.cpp
+++ b/lib/base/tcpsocket.cpp
@@ -62,9 +62,8 @@ void TcpSocket::Bind(const String& node, const String& service, int family)
 	    service.CStr(), &hints, &result);
 
 	if (rc != 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "getaddrinfo() failed with error code " << rc << ", \"" << gai_strerror(rc) << "\"";
-		Log(LogCritical, "TcpSocket",  msgbuf.str());
+		Log(LogCritical, "TcpSocket")
+		    << "getaddrinfo() failed with error code " << rc << ", \"" << gai_strerror(rc) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getaddrinfo")
@@ -118,9 +117,8 @@ void TcpSocket::Bind(const String& node, const String& service, int family)
 	freeaddrinfo(result);
 
 	if (GetFD() == INVALID_SOCKET) {
-		std::ostringstream msgbuf;
-		msgbuf << "Invalid socket: " << Utility::FormatErrorNumber(error);
-		Log(LogCritical, "TcpSocket",  msgbuf.str());
+		Log(LogCritical, "TcpSocket")
+		    << "Invalid socket: " << Utility::FormatErrorNumber(error);
 
 #ifndef _WIN32
 		BOOST_THROW_EXCEPTION(socket_error()
@@ -155,9 +153,8 @@ void TcpSocket::Connect(const String& node, const String& service)
 	int rc = getaddrinfo(node.CStr(), service.CStr(), &hints, &result);
 
 	if (rc != 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "getaddrinfo() failed with error code " << rc << ", \"" << gai_strerror(rc) << "\"";
-		Log(LogCritical, "TcpSocket",  msgbuf.str());
+		Log(LogCritical, "TcpSocket")
+		    << "getaddrinfo() failed with error code " << rc << ", \"" << gai_strerror(rc) << "\"";
 
 		BOOST_THROW_EXCEPTION(socket_error()
 		    << boost::errinfo_api_function("getaddrinfo")
@@ -203,9 +200,8 @@ void TcpSocket::Connect(const String& node, const String& service)
 	freeaddrinfo(result);
 
 	if (GetFD() == INVALID_SOCKET) {
-		std::ostringstream msgbuf;
-		msgbuf << "Invalid socket: " << Utility::FormatErrorNumber(error);
-		Log(LogCritical, "TcpSocket",  msgbuf.str());
+		Log(LogCritical, "TcpSocket")
+		    << "Invalid socket: " << Utility::FormatErrorNumber(error);
 
 #ifndef _WIN32
 		BOOST_THROW_EXCEPTION(socket_error()
diff --git a/lib/base/threadpool.cpp b/lib/base/threadpool.cpp
index 77fb7d35c..d35bf69f4 100644
--- a/lib/base/threadpool.cpp
+++ b/lib/base/threadpool.cpp
@@ -133,11 +133,9 @@ void ThreadPool::WorkerThread::ThreadProc(Queue& queue)
 			if (wi.Callback)
 				wi.Callback();
 		} catch (const std::exception& ex) {
-			std::ostringstream msgbuf;
-			msgbuf << "Exception thrown in event handler: " << std::endl
-			       << DiagnosticInformation(ex);
-
-			Log(LogCritical, "ThreadPool", msgbuf.str());
+			Log(LogCritical, "ThreadPool")
+			    << "Exception thrown in event handler:\n"
+			    << DiagnosticInformation(ex);
 		} catch (...) {
 			Log(LogCritical, "ThreadPool", "Exception of unknown type thrown in event handler.");
 		}
@@ -172,14 +170,12 @@ void ThreadPool::WorkerThread::ThreadProc(Queue& queue)
 		int divctx = usage_end.ru_nivcsw - usage_start.ru_nivcsw;
 #	endif /* RUSAGE_THREAD */
 		if (et - st > 0.5) {
-			std::ostringstream msgbuf;
+			Log(LogWarning, "ThreadPool")
 #	ifdef RUSAGE_THREAD
-			msgbuf << "Event call took user:" << duser << "s, system:" << dsys << "s, wait:" << dwait << "s, minor_faults:" << dminfaults << ", major_faults:" << dmajfaults << ", voluntary_csw:" << dvctx << ", involuntary_csw:" << divctx;
+			    << "Event call took user:" << duser << "s, system:" << dsys << "s, wait:" << dwait << "s, minor_faults:" << dminfaults << ", major_faults:" << dmajfaults << ", voluntary_csw:" << dvctx << ", involuntary_csw:" << divctx;
 #	else
-			msgbuf << "Event call took " << (et - st) << "s";
+			    << "Event call took " << (et - st) << "s";
 #	endif /* RUSAGE_THREAD */
-
-			Log(LogWarning, "ThreadPool", msgbuf.str());
 		}
 #endif /* _DEBUG */
 	}
@@ -293,9 +289,8 @@ void ThreadPool::ManagerThreadProc(void)
 					tthreads = m_MaxThreads / (sizeof(m_Queues) / sizeof(m_Queues[0])) - alive;
 
 				if (tthreads != 0) {
-					std::ostringstream msgbuf;
-					msgbuf << "Thread pool; current: " << alive << "; adjustment: " << tthreads;
-					Log(LogNotice, "ThreadPool", msgbuf.str());
+					Log(LogNotice, "ThreadPool")
+					    << "Thread pool; current: " << alive << "; adjustment: " << tthreads;
 				}
 
 				for (int i = 0; i < -tthreads; i++)
@@ -320,12 +315,11 @@ void ThreadPool::ManagerThreadProc(void)
 		if (lastStats < now - 15) {
 			lastStats = now;
 
-			std::ostringstream msgbuf;
-			msgbuf << "Pool #" << m_ID << ": Pending tasks: " << total_pending << "; Average latency: "
-				<< (long)(total_avg_latency * 1000 / (sizeof(m_Queues) / sizeof(m_Queues[0]))) << "ms"
-				<< "; Threads: " << total_alive
-				<< "; Pool utilization: " << (total_utilization / (sizeof(m_Queues) / sizeof(m_Queues[0]))) << "%";
-			Log(LogNotice, "ThreadPool", msgbuf.str());
+			Log(LogNotice, "ThreadPool")
+			    << "Pool #" << m_ID << ": Pending tasks: " << total_pending << "; Average latency: "
+			    << (long)(total_avg_latency * 1000 / (sizeof(m_Queues) / sizeof(m_Queues[0]))) << "ms"
+			    << "; Threads: " << total_alive
+			    << "; Pool utilization: " << (total_utilization / (sizeof(m_Queues) / sizeof(m_Queues[0]))) << "%";
 		}
 	}
 }
diff --git a/lib/base/tlsutility.cpp b/lib/base/tlsutility.cpp
index 963de5536..582383704 100644
--- a/lib/base/tlsutility.cpp
+++ b/lib/base/tlsutility.cpp
@@ -86,8 +86,8 @@ shared_ptr<SSL_CTX> MakeSSLContext(const String& pubkey, const String& privkey,
 	SSL_CTX_set_mode(sslContext.get(), SSL_MODE_ENABLE_PARTIAL_WRITE | SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
 
 	if (!SSL_CTX_use_certificate_chain_file(sslContext.get(), pubkey.CStr())) {
-		msgbuf << "Error with public key file '" << pubkey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error with public key file '" << pubkey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("SSL_CTX_use_certificate_chain_file")
 		    << errinfo_openssl_error(ERR_peek_error())
@@ -95,8 +95,8 @@ shared_ptr<SSL_CTX> MakeSSLContext(const String& pubkey, const String& privkey,
 	}
 
 	if (!SSL_CTX_use_PrivateKey_file(sslContext.get(), privkey.CStr(), SSL_FILETYPE_PEM)) {
-		msgbuf << "Error with private key file '" << privkey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error with private key file '" << privkey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("SSL_CTX_use_PrivateKey_file")
 		    << errinfo_openssl_error(ERR_peek_error())
@@ -104,8 +104,8 @@ shared_ptr<SSL_CTX> MakeSSLContext(const String& pubkey, const String& privkey,
 	}
 
 	if (!SSL_CTX_check_private_key(sslContext.get())) {
-		msgbuf << "Error checking private key '" << privkey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error checking private key '" << privkey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("SSL_CTX_check_private_key")
 		    << errinfo_openssl_error(ERR_peek_error()));
@@ -113,8 +113,8 @@ shared_ptr<SSL_CTX> MakeSSLContext(const String& pubkey, const String& privkey,
 
 	if (!cakey.IsEmpty()) {
 		if (!SSL_CTX_load_verify_locations(sslContext.get(), cakey.CStr(), NULL)) {
-			msgbuf << "Error loading and verifying locations in ca key file '" << cakey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-			Log(LogCritical, "SSL", msgbuf.str());
+			Log(LogCritical, "SSL")
+			    << "Error loading and verifying locations in ca key file '" << cakey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 			BOOST_THROW_EXCEPTION(openssl_error()
 			    << boost::errinfo_api_function("SSL_CTX_load_verify_locations")
 			    << errinfo_openssl_error(ERR_peek_error())
@@ -125,8 +125,8 @@ shared_ptr<SSL_CTX> MakeSSLContext(const String& pubkey, const String& privkey,
 
 		cert_names = SSL_load_client_CA_file(cakey.CStr());
 		if (cert_names == NULL) {
-			msgbuf << "Error loading client ca key file '" << cakey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-			Log(LogCritical, "SSL", msgbuf.str());
+			Log(LogCritical, "SSL")
+			    << "Error loading client ca key file '" << cakey << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 			BOOST_THROW_EXCEPTION(openssl_error()
 			    << boost::errinfo_api_function("SSL_load_client_CA_file")
 			    << errinfo_openssl_error(ERR_peek_error())
@@ -147,7 +147,6 @@ shared_ptr<SSL_CTX> MakeSSLContext(const String& pubkey, const String& privkey,
  */
 void AddCRLToSSLContext(const shared_ptr<SSL_CTX>& context, const String& crlPath)
 {
-	std::ostringstream msgbuf;
 	char errbuf[120];
 	X509_STORE *x509_store = SSL_CTX_get_cert_store(context.get());
 
@@ -155,20 +154,20 @@ void AddCRLToSSLContext(const shared_ptr<SSL_CTX>& context, const String& crlPat
 	lookup = X509_STORE_add_lookup(x509_store, X509_LOOKUP_file());
 
 	if (!lookup) {
-		msgbuf << "Error adding X509 store lookup: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error adding X509 store lookup: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
-			<< boost::errinfo_api_function("X509_STORE_add_lookup")
-			<< errinfo_openssl_error(ERR_peek_error()));
+		    << boost::errinfo_api_function("X509_STORE_add_lookup")
+		    << errinfo_openssl_error(ERR_peek_error()));
 	}
 
 	if (X509_LOOKUP_load_file(lookup, crlPath.CStr(), X509_FILETYPE_PEM) != 0) {
-		msgbuf << "Error loading crl file '" << crlPath << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error loading crl file '" << crlPath << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
-			<< boost::errinfo_api_function("X509_LOOKUP_load_file")
-			<< errinfo_openssl_error(ERR_peek_error())
-			<< boost::errinfo_file_name(crlPath));
+		    << boost::errinfo_api_function("X509_LOOKUP_load_file")
+		    << errinfo_openssl_error(ERR_peek_error())
+		    << boost::errinfo_file_name(crlPath));
 	}
 
 	X509_VERIFY_PARAM *param = X509_VERIFY_PARAM_new();
@@ -185,7 +184,6 @@ void AddCRLToSSLContext(const shared_ptr<SSL_CTX>& context, const String& crlPat
  */
 String GetCertificateCN(const shared_ptr<X509>& certificate)
 {
-	std::ostringstream msgbuf;
 	char errbuf[120];
 	char buffer[256];
 
@@ -193,8 +191,8 @@ String GetCertificateCN(const shared_ptr<X509>& certificate)
 	    NID_commonName, buffer, sizeof(buffer));
 
 	if (rc == -1) {
-		msgbuf << "Error with x509 NAME getting text by NID: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error with x509 NAME getting text by NID: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("X509_NAME_get_text_by_NID")
 		    << errinfo_openssl_error(ERR_peek_error()));
@@ -211,22 +209,21 @@ String GetCertificateCN(const shared_ptr<X509>& certificate)
  */
 shared_ptr<X509> GetX509Certificate(const String& pemfile)
 {
-	std::ostringstream msgbuf;
 	char errbuf[120];
 	X509 *cert;
 	BIO *fpcert = BIO_new(BIO_s_file());
 
 	if (fpcert == NULL) {
-		msgbuf << "Error creating new BIO: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error creating new BIO: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("BIO_new")
 		    << errinfo_openssl_error(ERR_peek_error()));
 	}
 
 	if (BIO_read_filename(fpcert, pemfile.CStr()) < 0) {
-		msgbuf << "Error reading pem file '" << pemfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error reading pem file '" << pemfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("BIO_read_filename")
 		    << errinfo_openssl_error(ERR_peek_error())
@@ -235,8 +232,8 @@ shared_ptr<X509> GetX509Certificate(const String& pemfile)
 
 	cert = PEM_read_bio_X509_AUX(fpcert, NULL, NULL, NULL);
 	if (cert == NULL) {
-		msgbuf << "Error on bio X509 AUX reading pem file '" << pemfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error on bio X509 AUX reading pem file '" << pemfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
 		    << boost::errinfo_api_function("PEM_read_bio_X509_AUX")
 		    << errinfo_openssl_error(ERR_peek_error())
@@ -254,7 +251,8 @@ int MakeX509CSR(const String& cn, const String& keyfile, const String& csrfile,
 
 	RSA *rsa = RSA_generate_key(4096, RSA_F4, NULL, NULL);
 
-	Log(LogInformation, "base", "Writing private key to '" + keyfile + "'.");
+	Log(LogInformation, "base")
+	    << "Writing private key to '" << keyfile << "'.";
 
 	BIO *bio = BIO_new_file(const_cast<char *>(keyfile.CStr()), "w");
 	PEM_write_bio_RSAPrivateKey(bio, rsa, NULL, NULL, 0, NULL, NULL);
@@ -275,7 +273,8 @@ int MakeX509CSR(const String& cn, const String& keyfile, const String& csrfile,
 
 		X509_NAME_free(subject);
 
-		Log(LogInformation, "base", "Writing X509 certificate to '" + certfile + "'.");
+		Log(LogInformation, "base")
+		    << "Writing X509 certificate to '" << certfile << "'.";
 
 		bio = BIO_new(BIO_s_file());
 		BIO_write_filename(bio, const_cast<char *>(certfile.CStr()));
@@ -297,7 +296,8 @@ int MakeX509CSR(const String& cn, const String& keyfile, const String& csrfile,
 	
 		X509_REQ_sign(req, key, EVP_sha1());
 	
-		Log(LogInformation, "base", "Writing certificate signing request to '" + csrfile + "'.");
+		Log(LogInformation, "base")
+		    << "Writing certificate signing request to '" << csrfile << "'.";
 	
 		bio = BIO_new(BIO_s_file());
 		BIO_write_filename(bio, const_cast<char *>(csrfile.CStr()));
@@ -348,7 +348,6 @@ String GetIcingaCADir(void)
 
 shared_ptr<X509> CreateCertIcingaCA(EVP_PKEY *pubkey, X509_NAME *subject)
 {
-	std::stringstream msgbuf;
 	char errbuf[120];
 
 	String cadir = GetIcingaCADir();
@@ -360,16 +359,16 @@ shared_ptr<X509> CreateCertIcingaCA(EVP_PKEY *pubkey, X509_NAME *subject)
 	BIO *cakeybio = BIO_new_file(const_cast<char *>(cakeyfile.CStr()), "r");
 
 	if (!cakeybio) {
-		msgbuf << "Could not open CA key file '" << cakeyfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Could not open CA key file '" << cakeyfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		return shared_ptr<X509>();
 	}
 
 	rsa = PEM_read_bio_RSAPrivateKey(cakeybio, NULL, NULL, NULL);
 
 	if (!rsa) {
-		msgbuf << "Could not read RSA key from CA key file '" << cakeyfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Could not read RSA key from CA key file '" << cakeyfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		return shared_ptr<X509>();
 	}
 
@@ -415,33 +414,32 @@ String PBKDF2_SHA1(const String& password, const String& salt, int iterations)
 
 String SHA256(const String& s)
 {
-	std::ostringstream msgbuf;
 	char errbuf[120];
 	SHA256_CTX context;
 	unsigned char digest[SHA256_DIGEST_LENGTH];
 
 	if (!SHA256_Init(&context)) {
-		msgbuf << "Error on SHA256 Init: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error on SHA256 Init: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
-			<< boost::errinfo_api_function("SHA256_Init")
-			<< errinfo_openssl_error(ERR_peek_error()));
+		    << boost::errinfo_api_function("SHA256_Init")
+		    << errinfo_openssl_error(ERR_peek_error()));
 	}
 
 	if (!SHA256_Update(&context, (unsigned char*)s.CStr(), s.GetLength())) {
-		msgbuf << "Error on SHA256 Update: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error on SHA256 Update: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
-			<< boost::errinfo_api_function("SHA256_Update")
-			<< errinfo_openssl_error(ERR_peek_error()));
+		    << boost::errinfo_api_function("SHA256_Update")
+		    << errinfo_openssl_error(ERR_peek_error()));
 	}
 
 	if (!SHA256_Final(digest, &context)) {
-		msgbuf << "Error on SHA256 Final: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Error on SHA256 Final: " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		BOOST_THROW_EXCEPTION(openssl_error()
-			<< boost::errinfo_api_function("SHA256_Final")
-			<< errinfo_openssl_error(ERR_peek_error()));
+		    << boost::errinfo_api_function("SHA256_Final")
+		    << errinfo_openssl_error(ERR_peek_error()));
 	}
 
 	char output[SHA256_DIGEST_LENGTH*2+1];
diff --git a/lib/base/utility.cpp b/lib/base/utility.cpp
index b6b86ad37..a7ebcb8bc 100644
--- a/lib/base/utility.cpp
+++ b/lib/base/utility.cpp
@@ -304,7 +304,8 @@ Utility::LoadExtensionLibrary(const String& library)
 	path = "lib" + library + ".so";
 #endif /* _WIN32 */
 
-	Log(LogInformation, "Utility", "Loading library '" + path + "'");
+	Log(LogInformation, "Utility")
+	    << "Loading library '" << path << "'";
 
 #ifdef _WIN32
 	HMODULE hModule = LoadLibrary(path.CStr());
diff --git a/lib/base/workqueue.cpp b/lib/base/workqueue.cpp
index 17f05811e..39ca0cdbc 100644
--- a/lib/base/workqueue.cpp
+++ b/lib/base/workqueue.cpp
@@ -124,7 +124,8 @@ void WorkQueue::StatusTimerHandler(void)
 {
 	boost::mutex::scoped_lock lock(m_Mutex);
 
-	Log(LogNotice, "WorkQueue", "#" + Convert::ToString(m_ID) + " items: " + Convert::ToString(m_Items.size()));
+	Log(LogNotice, "WorkQueue")
+	    << "#" << m_ID << " items: " << m_Items.size();
 }
 
 void WorkQueue::WorkerThreadProc(void)
diff --git a/lib/cli/agentlistcommand.cpp b/lib/cli/agentlistcommand.cpp
index 132472aa4..e9647e6e0 100644
--- a/lib/cli/agentlistcommand.cpp
+++ b/lib/cli/agentlistcommand.cpp
@@ -50,7 +50,8 @@ String AgentListCommand::GetShortDescription(void) const
 int AgentListCommand::Run(const boost::program_options::variables_map& vm, const std::vector<std::string>& ap) const
 {
 	if (!ap.empty()) {
-		Log(LogWarning, "cli", "Ignoring parameters: " + boost::algorithm::join(ap, " "));
+		Log(LogWarning, "cli")
+		    << "Ignoring parameters: " << boost::algorithm::join(ap, " ");
 	}
 
 	return 0;
diff --git a/lib/cli/agentsetupcommand.cpp b/lib/cli/agentsetupcommand.cpp
index d86f7a02a..035e0698d 100644
--- a/lib/cli/agentsetupcommand.cpp
+++ b/lib/cli/agentsetupcommand.cpp
@@ -59,7 +59,8 @@ void AgentSetupCommand::InitParameters(boost::program_options::options_descripti
 int AgentSetupCommand::Run(const boost::program_options::variables_map& vm, const std::vector<std::string>& ap) const
 {
 	if (!ap.empty()) {
-		Log(LogWarning, "cli", "Ignoring parameters: " + boost::algorithm::join(ap, " "));
+		Log(LogWarning, "cli")
+		    << "Ignoring parameters: " << boost::algorithm::join(ap, " ");
 	}
 
 	return 0;
diff --git a/lib/cli/agentupdateconfigcommand.cpp b/lib/cli/agentupdateconfigcommand.cpp
index df2828cf9..829b74eb4 100644
--- a/lib/cli/agentupdateconfigcommand.cpp
+++ b/lib/cli/agentupdateconfigcommand.cpp
@@ -50,7 +50,8 @@ String AgentUpdateConfigCommand::GetShortDescription(void) const
 int AgentUpdateConfigCommand::Run(const boost::program_options::variables_map& vm, const std::vector<std::string>& ap) const
 {
 	if (!ap.empty()) {
-		Log(LogWarning, "cli", "Ignoring parameters: " + boost::algorithm::join(ap, " "));
+		Log(LogWarning, "cli")
+		    << "Ignoring parameters: " << boost::algorithm::join(ap, " ");
 	}
 
 	return 0;
diff --git a/lib/cli/agentwizardcommand.cpp b/lib/cli/agentwizardcommand.cpp
index 3e42ddcc1..3f900bff0 100644
--- a/lib/cli/agentwizardcommand.cpp
+++ b/lib/cli/agentwizardcommand.cpp
@@ -50,7 +50,8 @@ String AgentWizardCommand::GetShortDescription(void) const
 int AgentWizardCommand::Run(const boost::program_options::variables_map& vm, const std::vector<std::string>& ap) const
 {
 	if (!ap.empty()) {
-		Log(LogWarning, "cli", "Ignoring parameters: " + boost::algorithm::join(ap, " "));
+		Log(LogWarning, "cli")
+		    << "Ignoring parameters: " << boost::algorithm::join(ap, " ");
 	}
 
 	return 0;
diff --git a/lib/cli/daemoncommand.cpp b/lib/cli/daemoncommand.cpp
index 09841a860..df9bfe817 100644
--- a/lib/cli/daemoncommand.cpp
+++ b/lib/cli/daemoncommand.cpp
@@ -46,7 +46,8 @@ REGISTER_CLICOMMAND("daemon", DaemonCommand);
 
 static String LoadAppType(const String& typeSpec)
 {
-	Log(LogInformation, "cli", "Loading application type: " + typeSpec);
+	Log(LogInformation, "cli")
+	    << "Loading application type: " << typeSpec;
 
 	String::SizeType index = typeSpec.FindFirstOf('/');
 
@@ -141,7 +142,8 @@ static bool LoadConfigFiles(const boost::program_options::variables_map& vm, con
 		else
 			severity = LogCritical;
 
-		Log(severity, "config", Convert::ToString(errors) + " errors, " + Convert::ToString(warnings) + " warnings.");
+		Log(severity, "config")
+		    << errors << " errors, " << warnings << " warnings.";
 	}
 
 	if (!result)
@@ -183,9 +185,8 @@ static bool Daemonize(void)
 			Log(LogCritical, "cli", "The daemon could not be started. See log output for details.");
 			exit(EXIT_FAILURE);
 		} else if (ret == -1) {
-			std::ostringstream msgbuf;
-			msgbuf << "waitpid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-			Log(LogCritical, "cli",  msgbuf.str());
+			Log(LogCritical, "cli")
+			    << "waitpid() failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 			exit(EXIT_FAILURE);
 		}
 
@@ -313,14 +314,16 @@ int DaemonCommand::Run(const po::variables_map& vm, const std::vector<std::strin
 
 	Application::MakeVariablesConstant();
 
-	Log(LogInformation, "cli", "Icinga application loader (version: " + Application::GetVersion() + ")");
+	Log(LogInformation, "cli")
+	    << "Icinga application loader (version: " << Application::GetVersion() << ")";
 
 	String appType = LoadAppType(Application::GetApplicationType());
 
 	if (!vm.count("validate") && !vm.count("reload-internal")) {
 		pid_t runningpid = Application::ReadPidFile(Application::GetPidPath());
 		if (runningpid > 0) {
-			Log(LogCritical, "cli", "Another instance of Icinga already running with PID " + Convert::ToString(runningpid));
+			Log(LogCritical, "cli")
+			    << "Another instance of Icinga already running with PID " << runningpid;
 			return EXIT_FAILURE;
 		}
 	}
@@ -335,7 +338,8 @@ int DaemonCommand::Run(const po::variables_map& vm, const std::vector<std::strin
 
 	if(vm.count("reload-internal")) {
 		int parentpid = vm["reload-internal"].as<int>();
-		Log(LogInformation, "cli", "Terminating previous instance of Icinga (PID " + Convert::ToString(parentpid) + ")");
+		Log(LogInformation, "cli")
+		    << "Terminating previous instance of Icinga (PID " << parentpid << ")";
 		TerminateAndWaitForEnd(parentpid);
 		Log(LogInformation, "cli", "Previous instance has ended, taking over now.");
 	}
diff --git a/lib/cli/featuredisablecommand.cpp b/lib/cli/featuredisablecommand.cpp
index ceb99bbd7..6dbf231b8 100644
--- a/lib/cli/featuredisablecommand.cpp
+++ b/lib/cli/featuredisablecommand.cpp
@@ -69,7 +69,8 @@ int FeatureDisableCommand::Run(const boost::program_options::variables_map& vm,
 	}
 
 	if (!Utility::PathExists(features_enabled_dir) ) {
-		Log(LogCritical, "cli", "Cannot disable features. Path '" + features_enabled_dir + "' does not exist.");
+		Log(LogCritical, "cli")
+		    << "Cannot disable features. Path '" << features_enabled_dir << "' does not exist.";
 		return 0;
 	}
 
@@ -79,14 +80,16 @@ int FeatureDisableCommand::Run(const boost::program_options::variables_map& vm,
 		String target = features_enabled_dir + "/" + feature + ".conf";
 
 		if (!Utility::PathExists(target) ) {
-			Log(LogCritical, "cli", "Cannot disable feature '" + feature + "'. Target file '" + target + "' does not exist.");
+			Log(LogCritical, "cli")
+			    << "Cannot disable feature '" << feature << "'. Target file '" << target << "' does not exist.";
 			errors.push_back(feature);
 			continue;
 		}
 
 		if (unlink(target.CStr()) < 0) {
-			Log(LogCritical, "cli", "Cannot disable feature '" + feature + "'. Unlinking target file '" + target +
-			    "' failed with error code " + Convert::ToString(errno) + ", \"" + Utility::FormatErrorNumber(errno) + "\".");
+			Log(LogCritical, "cli")
+			    << "Cannot disable feature '" << feature << "'. Unlinking target file '" << target
+			    << "' failed with error code " << errno << ", \"" + Utility::FormatErrorNumber(errno) << "\".";
 			errors.push_back(feature);
 			continue;
 		}
@@ -96,7 +99,8 @@ int FeatureDisableCommand::Run(const boost::program_options::variables_map& vm,
 	}
 
 	if (!errors.empty()) {
-		Log(LogCritical, "cli", "Cannot disable feature(s): " + boost::algorithm::join(errors, " "));
+		Log(LogCritical, "cli")
+		    << "Cannot disable feature(s): " << boost::algorithm::join(errors, " ");
 		errors.clear();
 		return 1;
 	}
diff --git a/lib/cli/featureenablecommand.cpp b/lib/cli/featureenablecommand.cpp
index fdaa3f54f..ab790d960 100644
--- a/lib/cli/featureenablecommand.cpp
+++ b/lib/cli/featureenablecommand.cpp
@@ -65,12 +65,14 @@ int FeatureEnableCommand::Run(const boost::program_options::variables_map& vm, c
 	}
 
 	if (!Utility::PathExists(features_available_dir) ) {
-		Log(LogCritical, "cli", "Cannot parse available features. Path '" + features_available_dir + "' does not exist.");
+		Log(LogCritical, "cli")
+		    << "Cannot parse available features. Path '" << features_available_dir << "' does not exist.";
 		return 0;
 	}
 
 	if (!Utility::PathExists(features_enabled_dir) ) {
-		Log(LogCritical, "cli", "Cannot enable features. Path '" + features_enabled_dir + "' does not exist.");
+		Log(LogCritical, "cli")
+		    << "Cannot enable features. Path '" << features_enabled_dir << "' does not exist.";
 		return 0;
 	}
 
@@ -80,7 +82,8 @@ int FeatureEnableCommand::Run(const boost::program_options::variables_map& vm, c
 		String source = features_available_dir + "/" + feature + ".conf";
 
 		if (!Utility::PathExists(source) ) {
-			Log(LogCritical, "cli", "Cannot enable feature '" + feature + "'. Source file '" + source + "' does not exist.");
+			Log(LogCritical, "cli")
+			    << "Cannot enable feature '" << feature << "'. Source file '" << source + "' does not exist.";
 			errors.push_back(feature);
 			continue;
 		}
@@ -88,14 +91,16 @@ int FeatureEnableCommand::Run(const boost::program_options::variables_map& vm, c
 		String target = features_enabled_dir + "/" + feature + ".conf";
 
 		if (Utility::PathExists(target) ) {
-			Log(LogWarning, "cli", "Feature '" + feature + "' already enabled.");
+			Log(LogWarning, "cli")
+			    << "Feature '" << feature << "' already enabled.";
 			continue;
 		}
 
 #ifndef _WIN32
 		if (symlink(source.CStr(), target.CStr()) < 0) {
-			Log(LogCritical, "cli", "Cannot enable feature '" + feature + "'. Linking source '" + source + "' to target file '" + target +
-			    "' failed with error code " + Convert::ToString(errno) + ", \"" + Utility::FormatErrorNumber(errno) + "\".");
+			Log(LogCritical, "cli")
+			    << "Cannot enable feature '" << feature << "'. Linking source '" << source << "' to target file '" << target
+			    << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\".";
 			errors.push_back(feature);
 			continue;
 		}
@@ -103,7 +108,8 @@ int FeatureEnableCommand::Run(const boost::program_options::variables_map& vm, c
 		std::ofstream fp;
 		fp.open(target.CStr());
 		if (!fp) {
-			Log(LogCritical, "cli", "Cannot enable feature '" + feature + "'. Failed to open file '" + target + "'.");
+			Log(LogCritical, "cli")
+			    << "Cannot enable feature '" << feature << "'. Failed to open file '" << target << "'.";
 			errors.push_back(feature);
 			continue;
 		}
@@ -116,7 +122,8 @@ int FeatureEnableCommand::Run(const boost::program_options::variables_map& vm, c
 	}
 
 	if (!errors.empty()) {
-		Log(LogCritical, "cli", "Cannot enable feature(s): " + boost::algorithm::join(errors, " "));
+		Log(LogCritical, "cli")
+		    << "Cannot enable feature(s): " << boost::algorithm::join(errors, " ");
 		errors.clear();
 		return 1;
 	}
diff --git a/lib/cli/featurelistcommand.cpp b/lib/cli/featurelistcommand.cpp
index 58e651eab..03708a9ae 100644
--- a/lib/cli/featurelistcommand.cpp
+++ b/lib/cli/featurelistcommand.cpp
@@ -50,7 +50,8 @@ String FeatureListCommand::GetShortDescription(void) const
 int FeatureListCommand::Run(const boost::program_options::variables_map& vm, const std::vector<std::string>& ap) const
 {
 	if (!ap.empty()) {
-		Log(LogWarning, "cli", "Ignoring parameters: " + boost::algorithm::join(ap, " "));
+		Log(LogWarning, "cli")
+		    << "Ignoring parameters: " << boost::algorithm::join(ap, " ");
 	}
 
 	std::vector<String> available_features;
diff --git a/lib/cli/featureutility.cpp b/lib/cli/featureutility.cpp
index dcb689b4c..10bd89110 100644
--- a/lib/cli/featureutility.cpp
+++ b/lib/cli/featureutility.cpp
@@ -81,7 +81,8 @@ bool FeatureUtility::GetFeatures(FeatureType ftype, std::vector<String>& feature
 
 		if (!Utility::Glob(path + "/*.conf",
 		    boost::bind(&FeatureUtility::CollectFeatures, _1, boost::ref(features)), GlobFile)) {
-			Log(LogCritical, "cli", "Cannot access path '" + path + "'.");
+			Log(LogCritical, "cli")
+			    << "Cannot access path '" << path << "'.";
 			return false;
 		}
 	}
@@ -94,6 +95,7 @@ void FeatureUtility::CollectFeatures(const String& feature_file, std::vector<Str
 	String feature = Utility::BaseName(feature_file);
 	boost::algorithm::replace_all(feature, ".conf", "");
 
-	Log(LogDebug, "cli", "Adding feature: " + feature);
+	Log(LogDebug, "cli")
+	    << "Adding feature: " << feature;
 	features.push_back(feature);
 }
diff --git a/lib/cli/objectlistcommand.cpp b/lib/cli/objectlistcommand.cpp
index 8c122e8e8..a186bfe16 100644
--- a/lib/cli/objectlistcommand.cpp
+++ b/lib/cli/objectlistcommand.cpp
@@ -68,13 +68,15 @@ void ObjectListCommand::InitParameters(boost::program_options::options_descripti
 int ObjectListCommand::Run(const boost::program_options::variables_map& vm, const std::vector<std::string>& ap) const
 {
 	if (!ap.empty()) {
-		Log(LogWarning, "cli", "Ignoring parameters: " + boost::algorithm::join(ap, " "));
+		Log(LogWarning, "cli")
+		    << "Ignoring parameters: " << boost::algorithm::join(ap, " ");
 	}
 
 	String objectfile = Application::GetObjectsPath();
 
 	if (!Utility::PathExists(objectfile)) {
-		Log(LogCritical, "cli", "Cannot parse objects file '" + Application::GetObjectsPath() + "'.");
+		Log(LogCritical, "cli")
+		    << "Cannot open objects file '" << Application::GetObjectsPath() << "'.";
 		Log(LogCritical, "cli", "Run 'icinga2 daemon -C' to validate config and generate the cache file.");
 		return 1;
 	}
@@ -112,7 +114,8 @@ int ObjectListCommand::Run(const boost::program_options::variables_map& vm, cons
 		std::cout << "\n";
 	}
 
-	Log(LogNotice, "cli", "Parsed " + Convert::ToString(objects_count) + " objects.");
+	Log(LogNotice, "cli")
+	    << "Parsed " << objects_count << " objects.";
 
 	return 0;
 }
diff --git a/lib/cli/pkinewcacommand.cpp b/lib/cli/pkinewcacommand.cpp
index c7a106046..4277d6c92 100644
--- a/lib/cli/pkinewcacommand.cpp
+++ b/lib/cli/pkinewcacommand.cpp
@@ -48,12 +48,14 @@ int PKINewCACommand::Run(const boost::program_options::variables_map& vm, const
 	String cadir = Application::GetLocalStateDir() + "/lib/icinga2/ca";
 
 	if (Utility::PathExists(cadir)) {
-		Log(LogCritical, "base", "CA directory '" + cadir + "' already exists.");
+		Log(LogCritical, "base")
+		    << "CA directory '" << cadir << "' already exists.";
 		return 1;
 	}
 
 	if (!Utility::MkDirP(cadir, 0700)) {
-		Log(LogCritical, "base", "Could not create CA directory '" + cadir + "'.");
+		Log(LogCritical, "base")
+		    << "Could not create CA directory '" << cadir << "'.";
 		return 1;
 	}
 
@@ -61,7 +63,8 @@ int PKINewCACommand::Run(const boost::program_options::variables_map& vm, const
 
 	String serialpath = cadir + "/serial.txt";
 
-	Log(LogInformation, "cli", "Initializing serial file in '" + serialpath + "'.");
+	Log(LogInformation, "cli")
+	    << "Initializing serial file in '" << serialpath << "'.";
 
 	std::ofstream fp;
 	fp.open(serialpath.CStr());
diff --git a/lib/cli/pkirequestcommand.cpp b/lib/cli/pkirequestcommand.cpp
index 2ed8baeb1..c8aa02e9e 100644
--- a/lib/cli/pkirequestcommand.cpp
+++ b/lib/cli/pkirequestcommand.cpp
@@ -155,7 +155,8 @@ int PKIRequestCommand::Run(const boost::program_options::variables_map& vm, cons
 	fpcert.open(certfile.CStr());
 
 	if (!fpcert) {
-		Log(LogCritical, "cli", "Could not open certificate file '" + certfile + "' for writing.");
+		Log(LogCritical, "cli")
+		    << "Could not open certificate file '" << certfile << "' for writing.";
 		return 1;
 	}
 
@@ -166,7 +167,8 @@ int PKIRequestCommand::Run(const boost::program_options::variables_map& vm, cons
 	fpca.open(cafile.CStr());
 
 	if (!fpcert) {
-		Log(LogCritical, "cli", "Could not open CA certificate file '" + cafile + "' for writing.");
+		Log(LogCritical, "cli")
+		    << "Could not open CA certificate file '" << cafile << "' for writing.";
 		return 1;
 	}
 
diff --git a/lib/cli/pkisigncsrcommand.cpp b/lib/cli/pkisigncsrcommand.cpp
index 5b7ce8488..41ff0ed33 100644
--- a/lib/cli/pkisigncsrcommand.cpp
+++ b/lib/cli/pkisigncsrcommand.cpp
@@ -83,8 +83,8 @@ int PKISignCSRCommand::Run(const boost::program_options::variables_map& vm, cons
 	X509_REQ *req = PEM_read_bio_X509_REQ(csrbio, NULL, NULL, NULL);
 
 	if (!req) {
-		msgbuf << "Could not read X509 certificate request from '" + csrfile + "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
-		Log(LogCritical, "SSL", msgbuf.str());
+		Log(LogCritical, "SSL")
+		    << "Could not read X509 certificate request from '" << csrfile << "': " << ERR_peek_error() << ", \"" << ERR_error_string(ERR_peek_error(), errbuf) << "\"";
 		return 1;
 	}
 
@@ -100,7 +100,8 @@ int PKISignCSRCommand::Run(const boost::program_options::variables_map& vm, cons
 	fpcert.open(certfile.CStr());
 
 	if (!fpcert) {
-		Log(LogCritical, "cli", "Failed to open certificate file '" + certfile + "' for output");
+		Log(LogCritical, "cli")
+		    << "Failed to open certificate file '" << certfile << "' for output";
 		return 1;
 	}
 
diff --git a/lib/compat/checkresultreader.cpp b/lib/compat/checkresultreader.cpp
index d925300ca..4e9c68810 100644
--- a/lib/compat/checkresultreader.cpp
+++ b/lib/compat/checkresultreader.cpp
@@ -118,8 +118,8 @@ void CheckResultReader::ProcessCheckResultFile(const String& path) const
 	Host::Ptr host = Host::GetByName(attrs["host_name"]);
 
 	if (!host) {
-		Log(LogWarning, "CheckResultReader", "Ignoring checkresult file for host '" + attrs["host_name"] +
-		    "': Host does not exist.");
+		Log(LogWarning, "CheckResultReader")
+		    << "Ignoring checkresult file for host '" << attrs["host_name"] << "': Host does not exist.";
 
 		return;
 	}
@@ -127,8 +127,9 @@ void CheckResultReader::ProcessCheckResultFile(const String& path) const
 	Service::Ptr service = host->GetServiceByShortName(attrs["service_description"]);
 
 	if (!service) {
-		Log(LogWarning, "CheckResultReader", "Ignoring checkresult file for host '" + attrs["host_name"] +
-		    "', service '" + attrs["service_description"] + "': Service does not exist.");
+		Log(LogWarning, "CheckResultReader")
+		    << "Ignoring checkresult file for host '" << attrs["host_name"]
+		    << "', service '" << attrs["service_description"] << "': Service does not exist.";
 
 		return;
 	}
@@ -143,8 +144,9 @@ void CheckResultReader::ProcessCheckResultFile(const String& path) const
 
 	service->ProcessCheckResult(result);
 
-	Log(LogDebug, "CheckResultReader", "Processed checkresult file for host '" + attrs["host_name"] +
-		    "', service '" + attrs["service_description"] + "'");
+	Log(LogDebug, "CheckResultReader")
+	    << "Processed checkresult file for host '" << attrs["host_name"]
+	    << "', service '" << attrs["service_description"] << "'";
 
 	{
 		ObjectLock olock(service);
diff --git a/lib/compat/compatlogger.cpp b/lib/compat/compatlogger.cpp
index 108f5ef17..40dc58f60 100644
--- a/lib/compat/compatlogger.cpp
+++ b/lib/compat/compatlogger.cpp
@@ -321,7 +321,8 @@ void CompatLogger::FlappingHandler(const Checkable::Ptr& checkable, FlappingStat
 			flapping_state_str = "DISABLED";
 			break;
 		default:
-			Log(LogCritical, "CompatLogger", "Unknown flapping state: " + Convert::ToString(flapping_state));
+			Log(LogCritical, "CompatLogger")
+			    << "Unknown flapping state: " << flapping_state;
 			return;
 	}
 
@@ -434,15 +435,18 @@ void CompatLogger::ReopenFile(bool rotate)
 		if (rotate) {
 			String archiveFile = GetLogDir() + "/archives/icinga-" + Utility::FormatDateTime("%m-%d-%Y-%H", Utility::GetTime()) + ".log";
 
-			Log(LogNotice, "CompatLogger", "Rotating compat log file '" + tempFile + "' -> '" + archiveFile + "'");
+			Log(LogNotice, "CompatLogger")
+			    << "Rotating compat log file '" << tempFile << "' -> '" << archiveFile << "'";
+
 			(void) rename(tempFile.CStr(), archiveFile.CStr());
 		}
 	}
 
 	m_OutputFile.open(tempFile.CStr(), std::ofstream::app);
 
-	if (!m_OutputFile.good()) {
-		Log(LogWarning, "CompatLogger", "Could not open compat log file '" + tempFile + "' for writing. Log output will be lost.");
+	if (!m_OutputFile) {
+		Log(LogWarning, "CompatLogger")
+		    << "Could not open compat log file '" << tempFile << "' for writing. Log output will be lost.";
 
 		return;
 	}
@@ -536,8 +540,10 @@ void CompatLogger::ScheduleNextRotation(void)
 
 	time_t ts = mktime(&tmthen);
 
-	Log(LogNotice, "CompatLogger", "Rescheduling rotation timer for compat log '"
-	    + GetName() + "' to '" + Utility::FormatDateTime("%Y/%m/%d %H:%M:%S %z", ts) + "'");
+	Log(LogNotice, "CompatLogger")
+	    << "Rescheduling rotation timer for compat log '"
+	    << GetName() << "' to '" << Utility::FormatDateTime("%Y/%m/%d %H:%M:%S %z", ts) << "'";
+
 	m_RotationTimer->Reschedule(ts);
 }
 
diff --git a/lib/compat/externalcommandlistener.cpp b/lib/compat/externalcommandlistener.cpp
index 2a3dd68cf..6cdd4a5d7 100644
--- a/lib/compat/externalcommandlistener.cpp
+++ b/lib/compat/externalcommandlistener.cpp
@@ -81,18 +81,16 @@ void ExternalCommandListener::CommandPipeThread(const String& commandPath)
 	mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 
 	if (!fifo_ok && mkfifo(commandPath.CStr(), S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) < 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "mkfifo() for fifo path '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "ExternalCommandListener",  msgbuf.str());
+		Log(LogCritical, "ExternalCommandListener")
+		    << "mkfifo() for fifo path '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 		return;
 	}
 
 	/* mkfifo() uses umask to mask off some bits, which means we need to chmod() the
 	 * fifo to get the right mask. */
 	if (chmod(commandPath.CStr(), mode) < 0) {
-		std::ostringstream msgbuf;
-		msgbuf << "chmod() on fifo '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-		Log(LogCritical, "ExternalCommandListener",  msgbuf.str());
+		Log(LogCritical, "ExternalCommandListener")
+		    << "chmod() on fifo '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 		return;
 	}
 
@@ -104,18 +102,16 @@ void ExternalCommandListener::CommandPipeThread(const String& commandPath)
 		} while (fd < 0 && errno == EINTR);
 
 		if (fd < 0) {
-			std::ostringstream msgbuf;
-			msgbuf << "open() for fifo path '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-			Log(LogCritical, "ExternalCommandListener",  msgbuf.str());
+			Log(LogCritical, "ExternalCommandListener")
+			    << "open() for fifo path '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 			return;
 		}
 
 		FILE *fp = fdopen(fd, "r");
 
 		if (fp == NULL) {
-			std::ostringstream msgbuf;
-			msgbuf << "fdopen() for fifo path '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-			Log(LogCritical, "ExternalCommandListener",  msgbuf.str());
+			Log(LogCritical, "ExternalCommandListener")
+			    << "fdopen() for fifo path '" << commandPath << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 			return;
 		}
 
@@ -131,13 +127,13 @@ void ExternalCommandListener::CommandPipeThread(const String& commandPath)
 			String command = line;
 
 			try {
-				Log(LogInformation, "ExternalCommandListener", "Executing external command: " + command);
+				Log(LogInformation, "ExternalCommandListener")
+				    << "Executing external command: " << command;
 
 				ExternalCommandProcessor::Execute(command);
 			} catch (const std::exception& ex) {
-				std::ostringstream msgbuf;
-				msgbuf << "External command failed." << DiagnosticInformation(ex);
-				Log(LogWarning, "ExternalCommandListener", msgbuf.str());
+				Log(LogWarning, "ExternalCommandListener")
+				    << "External command failed." << DiagnosticInformation(ex);
 			}
 		}
 
diff --git a/lib/compat/statusdatawriter.cpp b/lib/compat/statusdatawriter.cpp
index 5fb97407e..4db6397c4 100644
--- a/lib/compat/statusdatawriter.cpp
+++ b/lib/compat/statusdatawriter.cpp
@@ -693,7 +693,8 @@ void StatusDataWriter::UpdateObjectsCache(void)
 		Checkable::Ptr parent = dep->GetParent();
 
 		if (!parent) {
-			Log(LogDebug, "StatusDataWriter", "Missing parent for dependency '" + dep->GetName() + "'.");
+			Log(LogDebug, "StatusDataWriter")
+			    << "Missing parent for dependency '" << dep->GetName() << "'.";
 			continue;
 		}
 
@@ -704,8 +705,9 @@ void StatusDataWriter::UpdateObjectsCache(void)
 		Checkable::Ptr child = dep->GetChild();
 
 		if (!child) {
+			Log(LogDebug, "StatusDataWriter")
+			    << "Missing child for dependency '" << dep->GetName() << "'.";
 			continue;
-			Log(LogDebug, "StatusDataWriter", "Missing child for dependency '" + dep->GetName() + "'.");
 		}
 
 		Host::Ptr child_host;
@@ -840,5 +842,6 @@ void StatusDataWriter::StatusTimerHandler(void)
 		    << boost::errinfo_file_name(statuspathtmp));
 	}
 
-	Log(LogNotice, "StatusDataWriter", "Writing status.dat file took " + Utility::FormatDuration(Utility::GetTime() - start));
+	Log(LogNotice, "StatusDataWriter")
+	    << "Writing status.dat file took " << Utility::FormatDuration(Utility::GetTime() - start);
 }
diff --git a/lib/config/configcompiler.cpp b/lib/config/configcompiler.cpp
index c58b876bd..9d61ec2da 100644
--- a/lib/config/configcompiler.cpp
+++ b/lib/config/configcompiler.cpp
@@ -200,7 +200,8 @@ void ConfigCompiler::CompileFile(const String& path, const String& zone)
 			<< boost::errinfo_errno(errno)
 			<< boost::errinfo_file_name(path));
 
-	Log(LogInformation, "ConfigCompiler", "Compiling config file: " + path);
+	Log(LogInformation, "ConfigCompiler")
+	    << "Compiling config file: " << path;
 
 	return CompileStream(path, &stream, zone);
 }
@@ -225,7 +226,8 @@ void ConfigCompiler::CompileText(const String& path, const String& text, const S
  */
 void ConfigCompiler::AddIncludeSearchDir(const String& dir)
 {
-	Log(LogInformation, "ConfigCompiler", "Adding include search dir: " + dir);
+	Log(LogInformation, "ConfigCompiler")
+	    << "Adding include search dir: " << dir;
 
 	m_IncludeSearchDirs.push_back(dir);
 }
diff --git a/lib/config/configitem.cpp b/lib/config/configitem.cpp
index eb3c2af78..7dd1a7816 100644
--- a/lib/config/configitem.cpp
+++ b/lib/config/configitem.cpp
@@ -172,7 +172,8 @@ DynamicObject::Ptr ConfigItem::Commit(void)
 	ASSERT(!OwnsLock());
 
 #ifdef _DEBUG
-	Log(LogDebug, "ConfigItem", "Commit called for ConfigItem Type=" + GetType() + ", Name=" + GetName());
+	Log(LogDebug, "ConfigItem")
+	    << "Commit called for ConfigItem Type=" << GetType() << ", Name=" << GetName();
 #endif /* _DEBUG */
 
 	/* Make sure the type is valid. */
@@ -282,7 +283,8 @@ void ConfigItem::ValidateItem(void)
 
 void ConfigItem::WriteObjectsFile(const String& filename)
 {
-	Log(LogInformation, "ConfigItem", "Dumping config items to file '" + filename + "'");
+	Log(LogInformation, "ConfigItem")
+	    << "Dumping config items to file '" << filename << "'";
 
 	String tempFilename = filename + ".tmp";
 
@@ -398,7 +400,8 @@ bool ConfigItem::ValidateItems(const String& objectsFile)
 	BOOST_FOREACH(const DynamicType::Ptr& type, DynamicType::GetTypes()) {
 		int count = std::distance(type->GetObjects().first, type->GetObjects().second);
 		if (count > 0)
-			Log(LogInformation, "ConfigItem", "Checked " + Convert::ToString(count) + " " + type->GetName() + "(s).");
+			Log(LogInformation, "ConfigItem")
+			    << "Checked " << count << " " << type->GetName() << "(s).";
 	}
 
 	return !ConfigCompilerContext::GetInstance()->HasErrors();
@@ -413,7 +416,8 @@ bool ConfigItem::ActivateItems(void)
 	try {
 		DynamicObject::RestoreObjects(Application::GetStatePath());
 	} catch (const std::exception& ex) {
-		Log(LogCritical, "ConfigItem", "Failed to restore state file: " + DiagnosticInformation(ex));
+		Log(LogCritical, "ConfigItem")
+		    << "Failed to restore state file: " << DiagnosticInformation(ex);
 	}
 
 	Log(LogInformation, "ConfigItem", "Triggering Start signal for config items");
@@ -426,7 +430,8 @@ bool ConfigItem::ActivateItems(void)
 				continue;
 
 #ifdef _DEBUG
-			Log(LogDebug, "ConfigItem", "Activating object '" + object->GetName() + "' of type '" + object->GetType()->GetName() + "'");
+			Log(LogDebug, "ConfigItem")
+			    << "Activating object '" << object->GetName() << "' of type '" << object->GetType()->GetName() << "'";
 #endif /* _DEBUG */
 			upq.Enqueue(boost::bind(&DynamicObject::Activate, object));
 		}
diff --git a/lib/config/expression.cpp b/lib/config/expression.cpp
index 090476e0f..3e0b19572 100644
--- a/lib/config/expression.cpp
+++ b/lib/config/expression.cpp
@@ -52,7 +52,8 @@ Value Expression::Evaluate(const Dictionary::Ptr& locals, DebugHint *dhint) cons
 		if (m_Operator != &Expression::OpLiteral) {
 			std::ostringstream msgbuf;
 			ShowCodeFragment(msgbuf, m_DebugInfo, false);
-			Log(LogDebug, "Expression", "Executing:\n" + msgbuf.str());
+			Log(LogDebug, "Expression")
+			    << "Executing:\n" << msgbuf.str();
 		}
 #endif /* _DEBUG */
 
diff --git a/lib/db_ido/dbconnection.cpp b/lib/db_ido/dbconnection.cpp
index f5c13bc43..60af3a7bf 100644
--- a/lib/db_ido/dbconnection.cpp
+++ b/lib/db_ido/dbconnection.cpp
@@ -46,7 +46,9 @@ void DbConnection::OnConfigLoaded(void)
 	DynamicObject::OnConfigLoaded();
 
 	if (!GetEnableHa()) {
-		Log(LogDebug, "DbConnection", "HA functionality disabled. Won't pause IDO connection: " + GetName());
+		Log(LogDebug, "DbConnection")
+		    << "HA functionality disabled. Won't pause IDO connection: " << GetName();
+
 		SetHAMode(HARunEverywhere);
 	}
 }
@@ -62,7 +64,8 @@ void DbConnection::Resume(void)
 {
 	DynamicObject::Resume();
 
-	Log(LogInformation, "DbConnection", "Resuming IDO connection: " + GetName());
+	Log(LogInformation, "DbConnection")
+	    << "Resuming IDO connection: " << GetName();
 
 	m_CleanUpTimer = make_shared<Timer>();
 	m_CleanUpTimer->SetInterval(60);
@@ -74,7 +77,8 @@ void DbConnection::Pause(void)
 {
 	DynamicObject::Pause();
 
-	Log(LogInformation, "DbConnection", "Pausing IDO connection: " + GetName());
+	Log(LogInformation, "DbConnection")
+	     << "Pausing IDO connection: " << GetName();
 
 	m_CleanUpTimer.reset();
 }
@@ -160,7 +164,8 @@ void DbConnection::ProgramStatusHandler(void)
 
 	BOOST_FOREACH(const Dictionary::Pair& kv, vars) {
 		if (!kv.first.IsEmpty()) {
-			Log(LogDebug, "DbConnection", "icinga application customvar key: '" + kv.first + "' value: '" + Convert::ToString(kv.second) + "'");
+			Log(LogDebug, "DbConnection")
+			    << "icinga application customvar key: '" << kv.first << "' value: '" << kv.second << "'";
 
 			Dictionary::Ptr fields4 = make_shared<Dictionary>();
 			fields4->Set("varname", Convert::ToString(kv.first));
@@ -211,9 +216,10 @@ void DbConnection::CleanUpHandler(void)
 			continue;
 
 		CleanUpExecuteQuery(tables[i].name, tables[i].time_column, now - max_age);
-		Log(LogNotice, "DbConnection", "Cleanup (" + tables[i].name + "): " + Convert::ToString(max_age) +
-		    " now: " + Convert::ToString(now) +
-		    " old: " + Convert::ToString(now - max_age));
+		Log(LogNotice, "DbConnection")
+		    << "Cleanup (" << tables[i].name << "): " << max_age
+		    << " now: " << now
+		    << " old: " << now - max_age;
 	}
 
 }
diff --git a/lib/db_ido/dbevents.cpp b/lib/db_ido/dbevents.cpp
index a803ed2bc..40bf896d2 100644
--- a/lib/db_ido/dbevents.cpp
+++ b/lib/db_ido/dbevents.cpp
@@ -282,7 +282,8 @@ void DbEvents::AddCommentInternal(const Checkable::Ptr& checkable, const Comment
 		return;
 	}
 
-	Log(LogDebug, "DbEvents", "adding service comment (id = " + Convert::ToString(comment->GetLegacyId()) + ") for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "adding service comment (id = " << comment->GetLegacyId() << ") for '" << checkable->GetName() << "'";
 
 	/* add the service comment */
 	AddCommentByType(checkable, comment, historical);
@@ -340,7 +341,8 @@ void DbEvents::AddCommentByType(const DynamicObject::Ptr& object, const Comment:
 
 void DbEvents::RemoveComments(const Checkable::Ptr& checkable)
 {
-	Log(LogDebug, "DbEvents", "removing service comments for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "removing service comments for '" << checkable->GetName() << "'";
 
 	DbQuery query1;
 	query1.Table = "comments";
@@ -358,7 +360,8 @@ void DbEvents::RemoveComment(const Checkable::Ptr& checkable, const Comment::Ptr
 		return;
 	}
 
-	Log(LogDebug, "DbEvents", "removing service comment (id = " + Convert::ToString(comment->GetLegacyId()) + ") for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "removing service comment (id = " << comment->GetLegacyId() << ") for '" << checkable->GetName() << "'";
 
 	/* Status */
 	DbQuery query1;
@@ -427,7 +430,8 @@ void DbEvents::AddDowntimeInternal(const Checkable::Ptr& checkable, const Downti
 		return;
 	}
 
-	Log(LogDebug, "DbEvents", "adding service downtime (id = " + Convert::ToString(downtime->GetLegacyId()) + ") for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "adding service downtime (id = " << downtime->GetLegacyId() << ") for '" << checkable->GetName() << "'";
 
 	/* add the downtime */
 	AddDowntimeByType(checkable, downtime, historical);}
@@ -485,7 +489,8 @@ void DbEvents::AddDowntimeByType(const Checkable::Ptr& checkable, const Downtime
 
 void DbEvents::RemoveDowntimes(const Checkable::Ptr& checkable)
 {
-	Log(LogDebug, "DbEvents", "removing service downtimes for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "removing service downtimes for '" << checkable->GetName() << "'";
 
 	DbQuery query1;
 	query1.Table = "scheduleddowntime";
@@ -503,7 +508,8 @@ void DbEvents::RemoveDowntime(const Checkable::Ptr& checkable, const Downtime::P
 		return;
 	}
 
-	Log(LogDebug, "DbEvents", "removing service downtime (id = " + Convert::ToString(downtime->GetLegacyId()) + ") for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "removing service downtime (id = " << downtime->GetLegacyId() << ") for '" << checkable->GetName() << "'";
 
 	/* Status */
 	DbQuery query1;
@@ -547,7 +553,8 @@ void DbEvents::TriggerDowntime(const Checkable::Ptr& checkable, const Downtime::
 		return;
 	}
 
-	Log(LogDebug, "DbEvents", "updating triggered service downtime (id = " + Convert::ToString(downtime->GetLegacyId()) + ") for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "updating triggered service downtime (id = " << downtime->GetLegacyId() << ") for '" << checkable->GetName() << "'";
 
 	double now = Utility::GetTime();
 	std::pair<unsigned long, unsigned long> time_bag = CompatUtility::ConvertTimestamp(now);
@@ -629,7 +636,8 @@ void DbEvents::TriggerDowntime(const Checkable::Ptr& checkable, const Downtime::
 void DbEvents::AddAcknowledgementHistory(const Checkable::Ptr& checkable, const String& author, const String& comment,
     AcknowledgementType type, double expiry)
 {
-	Log(LogDebug, "DbEvents", "add acknowledgement history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add acknowledgement history for '" << checkable->GetName() << "'";
 
 	double now = Utility::GetTime();
 	std::pair<unsigned long, unsigned long> time_bag = CompatUtility::ConvertTimestamp(now);
@@ -669,14 +677,16 @@ void DbEvents::AddAcknowledgementHistory(const Checkable::Ptr& checkable, const
 
 void DbEvents::AddAcknowledgement(const Checkable::Ptr& checkable, AcknowledgementType type)
 {
-	Log(LogDebug, "DbEvents", "add acknowledgement for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add acknowledgement for '" << checkable->GetName() << "'";
 
 	AddAcknowledgementInternal(checkable, type, true);
 }
 
 void DbEvents::RemoveAcknowledgement(const Checkable::Ptr& checkable)
 {
-	Log(LogDebug, "DbEvents", "remove acknowledgement for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "remove acknowledgement for '" << checkable->GetName() << "'";
 
 	AddAcknowledgementInternal(checkable, AcknowledgementNone, false);
 }
@@ -716,7 +726,8 @@ void DbEvents::AddAcknowledgementInternal(const Checkable::Ptr& checkable, Ackno
 void DbEvents::AddNotificationHistory(const Notification::Ptr& notification, const Checkable::Ptr& checkable, const std::set<User::Ptr>& users, NotificationType type,
     const CheckResult::Ptr& cr, const String& author, const String& text)
 {
-	Log(LogDebug, "DbEvents", "add notification history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add notification history for '" << checkable->GetName() << "'";
 
 	/* start and end happen at the same time */
 	double now = Utility::GetTime();
@@ -768,7 +779,8 @@ void DbEvents::AddNotificationHistory(const Notification::Ptr& notification, con
 
 	/* filtered users */
 	BOOST_FOREACH(const User::Ptr& user, users) {
-		Log(LogDebug, "DbEvents", "add contact notification history for service '" + checkable->GetName() + "' and user '" + user->GetName() + "'.");
+		Log(LogDebug, "DbEvents")
+		    << "add contact notification history for service '" << checkable->GetName() << "' and user '" << user->GetName() << "'.";
 
 		Dictionary::Ptr fields2 = make_shared<Dictionary>();
 		fields2->Set("contact_object_id", user);
@@ -788,7 +800,8 @@ void DbEvents::AddNotificationHistory(const Notification::Ptr& notification, con
 /* statehistory */
 void DbEvents::AddStateChangeHistory(const Checkable::Ptr& checkable, const CheckResult::Ptr& cr, StateType type)
 {
-	Log(LogDebug, "DbEvents", "add state change history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add state change history for '" << checkable->GetName() << "'";
 
 	double now = Utility::GetTime();
 	std::pair<unsigned long, unsigned long> time_bag = CompatUtility::ConvertTimestamp(now);
@@ -897,7 +910,8 @@ void DbEvents::AddCheckResultLogHistory(const Checkable::Ptr& checkable, const C
 				type = LogEntryTypeServiceCritical;
 				break;
 			default:
-				Log(LogCritical, "DbEvents", "Unknown service state: " + Convert::ToString(state_after));
+				Log(LogCritical, "DbEvents")
+				    << "Unknown service state: " << state_after;
 				return;
 		}
 	} else {
@@ -922,7 +936,8 @@ void DbEvents::AddCheckResultLogHistory(const Checkable::Ptr& checkable, const C
 				type = LogEntryTypeHostDown;
 				break;
 			default:
-				Log(LogCritical, "DbEvents", "Unknown host state: " + Convert::ToString(state_after));
+				Log(LogCritical, "DbEvents")
+				    << "Unknown host state: " << state_after;
 				return;
 		}
 
@@ -1076,7 +1091,8 @@ void DbEvents::AddFlappingLogHistory(const Checkable::Ptr& checkable, FlappingSt
 			flapping_state_str = "DISABLED";
 			break;
 		default:
-			Log(LogCritical, "DbEvents", "Unknown flapping state: " + Convert::ToString(flapping_state));
+			Log(LogCritical, "DbEvents")
+			    << "Unknown flapping state: " << flapping_state;
 			return;
 	}
 
@@ -1106,7 +1122,8 @@ void DbEvents::AddFlappingLogHistory(const Checkable::Ptr& checkable, FlappingSt
 
 void DbEvents::AddLogHistory(const Checkable::Ptr& checkable, String buffer, LogEntryType type)
 {
-	Log(LogDebug, "DbEvents", "add log entry history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add log entry history for '" << checkable->GetName() << "'";
 
 	double now = Utility::GetTime();
 	std::pair<unsigned long, unsigned long> time_bag = CompatUtility::ConvertTimestamp(now);
@@ -1139,7 +1156,8 @@ void DbEvents::AddLogHistory(const Checkable::Ptr& checkable, String buffer, Log
 /* flappinghistory */
 void DbEvents::AddFlappingHistory(const Checkable::Ptr& checkable, FlappingState flapping_state)
 {
-	Log(LogDebug, "DbEvents", "add flapping history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add flapping history for '" << checkable->GetName() << "'";
 
 	double now = Utility::GetTime();
 	std::pair<unsigned long, unsigned long> time_bag = CompatUtility::ConvertTimestamp(now);
@@ -1167,7 +1185,8 @@ void DbEvents::AddFlappingHistory(const Checkable::Ptr& checkable, FlappingState
 			fields1->Set("reason_type", 2);
 			break;
 		default:
-			Log(LogDebug, "DbEvents", "Unhandled flapping state: " + Convert::ToString(flapping_state));
+			Log(LogDebug, "DbEvents")
+			    << "Unhandled flapping state: " << flapping_state;
 			return;
 	}
 
@@ -1199,7 +1218,8 @@ void DbEvents::AddServiceCheckHistory(const Checkable::Ptr& checkable, const Che
 	if (!cr)
 		return;
 
-	Log(LogDebug, "DbEvents", "add service check history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add service check history for '" << checkable->GetName() << "'";
 
 	Host::Ptr host;
 	Service::Ptr service;
@@ -1263,7 +1283,8 @@ void DbEvents::AddServiceCheckHistory(const Checkable::Ptr& checkable, const Che
 /* eventhandlers */
 void DbEvents::AddEventHandlerHistory(const Checkable::Ptr& checkable)
 {
-	Log(LogDebug, "DbEvents", "add eventhandler history for '" + checkable->GetName() + "'");
+	Log(LogDebug, "DbEvents")
+	    << "add eventhandler history for '" << checkable->GetName() << "'";
 
 	double now = Utility::GetTime();
 	std::pair<unsigned long, unsigned long> time_bag = CompatUtility::ConvertTimestamp(now);
diff --git a/lib/db_ido/dbobject.cpp b/lib/db_ido/dbobject.cpp
index f9c5a335b..d276513c9 100644
--- a/lib/db_ido/dbobject.cpp
+++ b/lib/db_ido/dbobject.cpp
@@ -127,7 +127,8 @@ void DbObject::SendStatusUpdate(void)
 	if (GetType()->GetTable() != "endpoint") {
 		String node = IcingaApplication::GetInstance()->GetNodeName();
 
-		Log(LogDebug, "DbObject", "Endpoint node: '" + node + "' status update for '" + GetObject()->GetName() + "'");
+		Log(LogDebug, "DbObject")
+		    << "Endpoint node: '" << node << "' status update for '" << GetObject()->GetName() << "'";
 
 		Endpoint::Ptr endpoint = Endpoint::GetByName(node);
 		if (endpoint)
@@ -160,7 +161,8 @@ void DbObject::SendVarsConfigUpdate(void)
 	Dictionary::Ptr vars = CompatUtility::GetCustomAttributeConfig(custom_var_object);
 
 	if (vars) {
-		Log(LogDebug, "DbObject", "Updating object vars for '" + custom_var_object->GetName() + "'");
+		Log(LogDebug, "DbObject")
+		    << "Updating object vars for '" << custom_var_object->GetName() << "'";
 
 		ObjectLock olock (vars);
 
@@ -168,8 +170,9 @@ void DbObject::SendVarsConfigUpdate(void)
 			if (!kv.first.IsEmpty()) {
 				int overridden = custom_var_object->IsVarOverridden(kv.first) ? 1 : 0;
 
-				Log(LogDebug, "DbObject", "object customvar key: '" + kv.first + "' value: '" + Convert::ToString(kv.second) +
-				    "' overridden: " + Convert::ToString(overridden));
+				Log(LogDebug, "DbObject")
+				    << "object customvar key: '" << kv.first << "' value: '" << kv.second
+				    << "' overridden: " << overridden;
 
 				Dictionary::Ptr fields = make_shared<Dictionary>();
 				fields->Set("varname", Convert::ToString(kv.first));
@@ -202,7 +205,8 @@ void DbObject::SendVarsStatusUpdate(void)
 	Dictionary::Ptr vars = CompatUtility::GetCustomAttributeConfig(custom_var_object);
 
 	if (vars) {
-		Log(LogDebug, "DbObject", "Updating object vars for '" + custom_var_object->GetName() + "'");
+		Log(LogDebug, "DbObject")
+		    << "Updating object vars for '" << custom_var_object->GetName() << "'";
 
 		ObjectLock olock (vars);
 
@@ -210,8 +214,9 @@ void DbObject::SendVarsStatusUpdate(void)
 			if (!kv.first.IsEmpty()) {
 				int overridden = custom_var_object->IsVarOverridden(kv.first) ? 1 : 0;
 
-				Log(LogDebug, "DbObject", "object customvar key: '" + kv.first + "' value: '" + Convert::ToString(kv.second) +
-				    "' overridden: " + Convert::ToString(overridden));
+				Log(LogDebug, "DbObject")
+				    << "object customvar key: '" << kv.first << "' value: '" << kv.second
+				    << "' overridden: " << overridden;
 
 				Dictionary::Ptr fields = make_shared<Dictionary>();
 				fields->Set("varname", Convert::ToString(kv.first));
@@ -322,7 +327,8 @@ void DbObject::VarsChangedHandler(const CustomVarObject::Ptr& object)
 {
 	DbObject::Ptr dbobj = GetOrCreateByObject(object);
 
-	Log(LogDebug, "DbObject", "Vars changed for object '" + object->GetName() + "'");
+	Log(LogDebug, "DbObject")
+	    << "Vars changed for object '" << object->GetName() << "'";
 
 	if (!dbobj)
 		return;
diff --git a/lib/db_ido/endpointdbobject.cpp b/lib/db_ido/endpointdbobject.cpp
index 90c477550..39ec869b3 100644
--- a/lib/db_ido/endpointdbobject.cpp
+++ b/lib/db_ido/endpointdbobject.cpp
@@ -62,7 +62,8 @@ Dictionary::Ptr EndpointDbObject::GetStatusFields(void) const
 	Dictionary::Ptr fields = make_shared<Dictionary>();
 	Endpoint::Ptr endpoint = static_pointer_cast<Endpoint>(GetObject());
 
-	Log(LogDebug, "EndpointDbObject", "update status for endpoint '" + endpoint->GetName() + "'");
+	Log(LogDebug, "EndpointDbObject")
+	    << "update status for endpoint '" << endpoint->GetName() << "'";
 
 	fields->Set("identity", endpoint->GetName());
 	fields->Set("node", IcingaApplication::GetInstance()->GetNodeName());
@@ -75,7 +76,8 @@ void EndpointDbObject::UpdateConnectedStatus(const Endpoint::Ptr& endpoint)
 {
 	bool connected = EndpointIsConnected(endpoint);
 
-	Log(LogDebug, "EndpointDbObject", "update is_connected=" + Convert::ToString(connected ? 1 : 0) + " for endpoint '" + endpoint->GetName() + "'");
+	Log(LogDebug, "EndpointDbObject")
+	    << "update is_connected=" << connected << " for endpoint '" << endpoint->GetName() << "'";
 
 	DbQuery query1;
 	query1.Table = "endpointstatus";
diff --git a/lib/db_ido/hostdbobject.cpp b/lib/db_ido/hostdbobject.cpp
index b3bd6bdd8..fda26ae26 100644
--- a/lib/db_ido/hostdbobject.cpp
+++ b/lib/db_ido/hostdbobject.cpp
@@ -184,7 +184,8 @@ void HostDbObject::OnConfigUpdate(void)
 		if (!parent)
 			continue;
 
-		Log(LogDebug, "HostDbObject", "host parents: " + parent->GetName());
+		Log(LogDebug, "HostDbObject")
+		    << "host parents: " << parent->GetName();
 
 		/* parents: host_id, parent_host_object_id */
 		Dictionary::Ptr fields1 = make_shared<Dictionary>();
@@ -201,19 +202,22 @@ void HostDbObject::OnConfigUpdate(void)
 	}
 
 	/* host dependencies */
-	Log(LogDebug, "HostDbObject", "host dependencies for '" + host->GetName() + "'");
+	Log(LogDebug, "HostDbObject")
+	    << "host dependencies for '" << host->GetName() << "'";
 
 	BOOST_FOREACH(const Dependency::Ptr& dep, host->GetDependencies()) {
 		Checkable::Ptr parent = dep->GetParent();
 
 		if (!parent) {
-			Log(LogDebug, "HostDbObject", "Missing parent for dependency '" + dep->GetName() + "'.");
+			Log(LogDebug, "HostDbObject")
+			    << "Missing parent for dependency '" << dep->GetName() << "'.";
 			continue;
 		}
 
 		int state_filter = dep->GetStateFilter();
 
-		Log(LogDebug, "HostDbObject", "parent host: " + parent->GetName());
+		Log(LogDebug, "HostDbObject")
+		    << "parent host: " << parent->GetName();
 
 		Dictionary::Ptr fields2 = make_shared<Dictionary>();
 		fields2->Set("host_object_id", parent);
@@ -232,10 +236,12 @@ void HostDbObject::OnConfigUpdate(void)
 		OnQuery(query2);
 	}
 
-	Log(LogDebug, "HostDbObject", "host contacts: " + host->GetName());
+	Log(LogDebug, "HostDbObject")
+	    << "host contacts: " << host->GetName();
 
 	BOOST_FOREACH(const User::Ptr& user, CompatUtility::GetCheckableNotificationUsers(host)) {
-		Log(LogDebug, "HostDbObject", "host contacts: " + user->GetName());
+		Log(LogDebug, "HostDbObject")
+		    << "host contacts: " << user->GetName();
 
 		Dictionary::Ptr fields_contact = make_shared<Dictionary>();
 		fields_contact->Set("host_id", DbValue::FromObjectInsertID(host));
@@ -250,10 +256,12 @@ void HostDbObject::OnConfigUpdate(void)
 		OnQuery(query_contact);
 	}
 
-	Log(LogDebug, "HostDbObject", "host contactgroups: " + host->GetName());
+	Log(LogDebug, "HostDbObject")
+	    << "host contactgroups: " << host->GetName();
 
 	BOOST_FOREACH(const UserGroup::Ptr& usergroup, CompatUtility::GetCheckableNotificationUserGroups(host)) {
-		Log(LogDebug, "HostDbObject", "host contactgroups: " + usergroup->GetName());
+		Log(LogDebug, "HostDbObject")
+		    << "host contactgroups: " << usergroup->GetName();
 
 		Dictionary::Ptr fields_contact = make_shared<Dictionary>();
 		fields_contact->Set("host_id", DbValue::FromObjectInsertID(host));
diff --git a/lib/db_ido/servicedbobject.cpp b/lib/db_ido/servicedbobject.cpp
index f8db77b10..d9229dd94 100644
--- a/lib/db_ido/servicedbobject.cpp
+++ b/lib/db_ido/servicedbobject.cpp
@@ -177,17 +177,20 @@ void ServiceDbObject::OnConfigUpdate(void)
 	Service::Ptr service = static_pointer_cast<Service>(GetObject());
 
 	/* service dependencies */
-	Log(LogDebug, "ServiceDbObject", "service dependencies for '" + service->GetName() + "'");
+	Log(LogDebug, "ServiceDbObject")
+	    << "service dependencies for '" << service->GetName() << "'";
 
 	BOOST_FOREACH(const Dependency::Ptr& dep, service->GetDependencies()) {
 		Checkable::Ptr parent = dep->GetParent();
 
 		if (!parent) {
-			Log(LogDebug, "ServiceDbObject", "Missing parent for dependency '" + dep->GetName() + "'.");
+			Log(LogDebug, "ServiceDbObject")
+			    << "Missing parent for dependency '" << dep->GetName() << "'.";
 			continue;
 		}
 
-		Log(LogDebug, "ServiceDbObject", "service parents: " + parent->GetName());
+		Log(LogDebug, "ServiceDbObject")
+		    << "service parents: " << parent->GetName();
 
 		int state_filter = dep->GetStateFilter();
 
@@ -212,10 +215,12 @@ void ServiceDbObject::OnConfigUpdate(void)
 	}
 
 	/* service contacts, contactgroups */
-	Log(LogDebug, "ServiceDbObject", "service contacts: " + service->GetName());
+	Log(LogDebug, "ServiceDbObject")
+	    << "service contacts: " << service->GetName();
 
 	BOOST_FOREACH(const User::Ptr& user, CompatUtility::GetCheckableNotificationUsers(service)) {
-		Log(LogDebug, "ServiceDbObject", "service contacts: " + user->GetName());
+		Log(LogDebug, "ServiceDbObject")
+		    << "service contacts: " << user->GetName();
 
 		Dictionary::Ptr fields_contact = make_shared<Dictionary>();
 		fields_contact->Set("service_id", DbValue::FromObjectInsertID(service));
@@ -233,7 +238,8 @@ void ServiceDbObject::OnConfigUpdate(void)
 	Log(LogDebug, "ServiceDbObject", "service contactgroups: " + service->GetName());
 
 	BOOST_FOREACH(const UserGroup::Ptr& usergroup, CompatUtility::GetCheckableNotificationUserGroups(service)) {
-		Log(LogDebug, "ServiceDbObject", "service contactgroups: " + usergroup->GetName());
+		Log(LogDebug, "ServiceDbObject")
+		    << "service contactgroups: " << usergroup->GetName();
 
 		Dictionary::Ptr fields_contact = make_shared<Dictionary>();
 		fields_contact->Set("service_id", DbValue::FromObjectInsertID(service));
diff --git a/lib/db_ido/userdbobject.cpp b/lib/db_ido/userdbobject.cpp
index a5481e142..53da290db 100644
--- a/lib/db_ido/userdbobject.cpp
+++ b/lib/db_ido/userdbobject.cpp
@@ -85,7 +85,8 @@ void UserDbObject::OnConfigUpdate(void)
 	User::Ptr user = static_pointer_cast<User>(GetObject());
 
 	/* contact addresses */
-	Log(LogDebug, "UserDbObject", "contact addresses for '" + user->GetName() + "'");
+	Log(LogDebug, "UserDbObject")
+	    << "contact addresses for '" << user->GetName() << "'";
 
 	Dictionary::Ptr vars = user->GetVars();
 
diff --git a/lib/db_ido_mysql/idomysqlconnection.cpp b/lib/db_ido_mysql/idomysqlconnection.cpp
index d80efd633..c67de4429 100644
--- a/lib/db_ido_mysql/idomysqlconnection.cpp
+++ b/lib/db_ido_mysql/idomysqlconnection.cpp
@@ -97,7 +97,8 @@ void IdoMysqlConnection::ExceptionHandler(boost::exception_ptr exp)
 {
 	Log(LogCritical, "IdoMysqlConnection", "Exception during database operation: Verify that your database is operational!");
 
-	Log(LogDebug, "IdoMysqlConnection", "Exception during database operation: " + DiagnosticInformation(exp));
+	Log(LogDebug, "IdoMysqlConnection")
+	    << "Exception during database operation: " << DiagnosticInformation(exp);
 
 	boost::mutex::scoped_lock lock(m_ConnectionMutex);
 
@@ -191,18 +192,16 @@ void IdoMysqlConnection::Reconnect(void)
 
 		/* connection */
 		if (!mysql_init(&m_Connection)) {
-			std::ostringstream msgbuf;
-			msgbuf << "mysql_init() failed: \"" << mysql_error(&m_Connection) << "\"";
-			Log(LogCritical, "IdoMysqlConnection", msgbuf.str());
+			Log(LogCritical, "IdoMysqlConnection")
+			    << "mysql_init() failed: \"" << mysql_error(&m_Connection) << "\"";
 
 			BOOST_THROW_EXCEPTION(std::bad_alloc());
 		}
 
 		if (!mysql_real_connect(&m_Connection, host, user, passwd, db, port, NULL, CLIENT_FOUND_ROWS)) {
-			std::ostringstream msgbuf;
-			msgbuf << "Connection to database '" << db << "' with user '" << user << "' on '" << host << ":" << port
+			Log(LogCritical, "IdoMysqlConnection")
+			    << "Connection to database '" << db << "' with user '" << user << "' on '" << host << ":" << port
 			    << "' failed: \"" << mysql_error(&m_Connection) << "\"";
-			Log(LogCritical, "IdoMysqlConnection", msgbuf.str());
 
 			BOOST_THROW_EXCEPTION(std::runtime_error(mysql_error(&m_Connection)));
 		}
@@ -225,8 +224,9 @@ void IdoMysqlConnection::Reconnect(void)
 		String version = row->Get("version");
 
 		if (Utility::CompareVersion(SCHEMA_VERSION, version) < 0) {
-			Log(LogCritical, "IdoMysqlConnection", "Schema version '" + version + "' does not match the required version '" +
-			   SCHEMA_VERSION + "'! Please check the upgrade documentation.");
+			Log(LogCritical, "IdoMysqlConnection")
+			    << "Schema version '" << version << "' does not match the required version '"
+			    << SCHEMA_VERSION << "'! Please check the upgrade documentation.";
 
 			Application::Exit(EXIT_FAILURE);
 		}
@@ -273,8 +273,8 @@ void IdoMysqlConnection::Reconnect(void)
 
 				double status_update_age = Utility::GetTime() - status_update_time;
 
-				Log(LogNotice, "IdoMysqlConnection", "Last update by '" +
-				    endpoint_name + "' was " + Convert::ToString(status_update_age) + "s ago.");
+				Log(LogNotice, "IdoMysqlConnection")
+				    << "Last update by '" << endpoint_name << "' was " << status_update_age << "s ago.";
 
 				if (status_update_age < GetFailoverTimeout()) {
 					mysql_close(&m_Connection);
@@ -285,8 +285,8 @@ void IdoMysqlConnection::Reconnect(void)
 
 				/* activate the IDO only, if we're authoritative in this zone */
 				if (IsPaused()) {
-					Log(LogNotice, "IdoMysqlConnection", "Local endpoint '" +
-					    my_endpoint->GetName() + "' is not authoritative, bailing out.");
+					Log(LogNotice, "IdoMysqlConnection")
+					    << "Local endpoint '" << my_endpoint->GetName() << "' is not authoritative, bailing out.";
 
 					mysql_close(&m_Connection);
 					m_Connected = false;
@@ -298,9 +298,8 @@ void IdoMysqlConnection::Reconnect(void)
 			Log(LogNotice, "IdoMysqlConnection", "Enabling IDO connection.");
 		}
 
-		std::ostringstream msgbuf;
-		msgbuf << "MySQL IDO instance id: " << static_cast<long>(m_InstanceID) << " (schema version: '" + version + "')";
-		Log(LogInformation, "IdoMysqlConnection", msgbuf.str());
+		Log(LogInformation, "IdoMysqlConnection")
+		    << "MySQL IDO instance id: " << static_cast<long>(m_InstanceID) << " (schema version: '" + version + "')";
 
 		/* set session time zone to utc */
 		Query("SET SESSION TIME_ZONE='+00:00'");
@@ -340,8 +339,9 @@ void IdoMysqlConnection::Reconnect(void)
 	/* deactivate all deleted configuration objects */
 	BOOST_FOREACH(const DbObject::Ptr& dbobj, active_dbobjs) {
 		if (dbobj->GetObject() == NULL) {
-			Log(LogNotice, "IdoMysqlConnection", "Deactivate deleted object name1: '" + Convert::ToString(dbobj->GetName1() +
-			    "' name2: '" + Convert::ToString(dbobj->GetName2() + "'.")));
+			Log(LogNotice, "IdoMysqlConnection")
+			    << "Deactivate deleted object name1: '" << dbobj->GetName1()
+			    << "' name2: '" << dbobj->GetName2() + "'.";
 			DeactivateObject(dbobj);
 		}
 	}
diff --git a/lib/db_ido_pgsql/idopgsqlconnection.cpp b/lib/db_ido_pgsql/idopgsqlconnection.cpp
index 28eb34470..b01f6d88d 100644
--- a/lib/db_ido_pgsql/idopgsqlconnection.cpp
+++ b/lib/db_ido_pgsql/idopgsqlconnection.cpp
@@ -99,7 +99,8 @@ void IdoPgsqlConnection::ExceptionHandler(boost::exception_ptr exp)
 {
 	Log(LogWarning, "IdoPgsqlConnection", "Exception during database operation: Verify that your database is operational!");
 
-	Log(LogDebug, "IdoPgsqlConnection", "Exception during database operation: " + DiagnosticInformation(exp));
+	Log(LogDebug, "IdoPgsqlConnection")
+	    << "Exception during database operation: " << DiagnosticInformation(exp);
 
 	boost::mutex::scoped_lock lock(m_ConnectionMutex);
 
@@ -202,10 +203,9 @@ void IdoPgsqlConnection::Reconnect(void)
 			PQfinish(m_Connection);
 			m_Connection = NULL;
 
-			std::ostringstream msgbuf;
-			msgbuf << "Connection to database '" << db << "' with user '" << user << "' on '" << host << ":" << port
+			Log(LogCritical, "IdoPgsqlConnection")
+			    << "Connection to database '" << db << "' with user '" << user << "' on '" << host << ":" << port
 			    << "' failed: \"" << message << "\"";
-			Log(LogCritical, "IdoPgsqlConnection", msgbuf.str());
 
 			BOOST_THROW_EXCEPTION(std::runtime_error(message));
 		}
@@ -224,8 +224,9 @@ void IdoPgsqlConnection::Reconnect(void)
 		String version = row->Get("version");
 
 		if (Utility::CompareVersion(SCHEMA_VERSION, version) < 0) {
-			Log(LogCritical, "IdoPgsqlConnection", "Schema version '" + version + "' does not match the required version '" +
-			    SCHEMA_VERSION + "'! Please check the upgrade documentation.");
+			Log(LogCritical, "IdoPgsqlConnection")
+			    << "Schema version '" << version << "' does not match the required version '"
+			    << SCHEMA_VERSION << "'! Please check the upgrade documentation.";
 
 			Application::Exit(EXIT_FAILURE);
 		}
@@ -269,8 +270,8 @@ void IdoPgsqlConnection::Reconnect(void)
 
 				double status_update_age = Utility::GetTime() - status_update_time;
 
-				Log(LogNotice, "IdoPgsqlConnection", "Last update by '" +
-				    endpoint_name + "' was " + Convert::ToString(status_update_age) + "s ago.");
+				Log(LogNotice, "IdoPgsqlConnection")
+				    << "Last update by '" << endpoint_name << "' was " << status_update_age << "s ago.";
 
 				if (status_update_age < GetFailoverTimeout()) {
 					PQfinish(m_Connection);
@@ -281,8 +282,8 @@ void IdoPgsqlConnection::Reconnect(void)
 
 				/* activate the IDO only, if we're authoritative in this zone */
 				if (IsPaused()) {
-					Log(LogNotice, "IdoPgsqlConnection", "Local endpoint '" +
-					    my_endpoint->GetName() + "' is not authoritative, bailing out.");
+					Log(LogNotice, "IdoPgsqlConnection")
+					    << "Local endpoint '" << my_endpoint->GetName() << "' is not authoritative, bailing out.";
 
 					PQfinish(m_Connection);
 					m_Connection = NULL;
@@ -294,9 +295,8 @@ void IdoPgsqlConnection::Reconnect(void)
 			Log(LogNotice, "IdoPgsqlConnection", "Enabling IDO connection.");
 		}
 
-		std::ostringstream msgbuf;
-		msgbuf << "pgSQL IDO instance id: " << static_cast<long>(m_InstanceID) << " (schema version: '" + version + "')";
-		Log(LogInformation, "IdoPgsqlConnection", msgbuf.str());
+		Log(LogInformation, "IdoPgsqlConnection")
+		    << "pgSQL IDO instance id: " << static_cast<long>(m_InstanceID) << " (schema version: '" + version + "')";
 
 		/* record connection */
 		Query("INSERT INTO " + GetTablePrefix() + "conninfo " +
@@ -336,8 +336,9 @@ void IdoPgsqlConnection::Reconnect(void)
 	/* deactivate all deleted configuration objects */
 	BOOST_FOREACH(const DbObject::Ptr& dbobj, active_dbobjs) {
 		if (dbobj->GetObject() == NULL) {
-			Log(LogNotice, "IdoPgsqlConnection", "Deactivate deleted object name1: '" + Convert::ToString(dbobj->GetName1() +
-			    "' name2: '" + Convert::ToString(dbobj->GetName2() + "'.")));
+			Log(LogNotice, "IdoPgsqlConnection")
+			    << "Deactivate deleted object name1: '" << dbobj->GetName1()
+			    << "' name2: '" << dbobj->GetName2() + "'.";
 			DeactivateObject(dbobj);
 		}
 	}
@@ -352,15 +353,15 @@ IdoPgsqlResult IdoPgsqlConnection::Query(const String& query)
 {
 	AssertOnWorkQueue();
 
-	Log(LogDebug, "IdoPgsqlConnection", "Query: " + query);
+	Log(LogDebug, "IdoPgsqlConnection")
+	    << "Query: " << query;
 
 	PGresult *result = PQexec(m_Connection, query.CStr());
 
 	if (!result) {
 		String message = PQerrorMessage(m_Connection);
-		std::ostringstream msgbuf;
-		msgbuf << "Error \"" << message << "\" when executing query \"" << query << "\"";
-		Log(LogCritical, "IdoPgsqlConnection", msgbuf.str());
+		Log(LogCritical, "IdoPgsqlConnection")
+		    << "Error \"" << message << "\" when executing query \"" << query << "\"";
 
 		BOOST_THROW_EXCEPTION(
 		    database_error()
@@ -381,9 +382,8 @@ IdoPgsqlResult IdoPgsqlConnection::Query(const String& query)
 		String message = PQresultErrorMessage(result);
 		PQclear(result);
 
-		std::ostringstream msgbuf;
-		msgbuf << "Error \"" << message << "\" when executing query \"" << query << "\"";
-		Log(LogCritical, "IdoPgsqlConnection", msgbuf.str());
+		Log(LogCritical, "IdoPgsqlConnection")
+		    << "Error \"" << message << "\" when executing query \"" << query << "\"";
 
 		BOOST_THROW_EXCEPTION(
 		    database_error()
@@ -405,9 +405,8 @@ DbReference IdoPgsqlConnection::GetSequenceValue(const String& table, const Stri
 
 	ASSERT(row);
 
-	std::ostringstream msgbuf;
-	msgbuf << "Sequence Value: " << row->Get("id");
-	Log(LogDebug, "IdoPgsqlConnection", msgbuf.str());
+	Log(LogDebug, "IdoPgsqlConnection")
+	    << "Sequence Value: " << row->Get("id");
 
 	return DbReference(Convert::ToLong(row->Get("id")));
 }
@@ -713,8 +712,10 @@ void IdoPgsqlConnection::InternalExecuteQuery(const DbQuery& query, DbQueryType
 
 	if (type == DbQueryInsert && query.Table == "notifications" && query.NotificationObject) { // FIXME remove hardcoded table name
 		String idField = "notification_id";
-		SetNotificationInsertID(query.NotificationObject, GetSequenceValue(GetTablePrefix() + query.Table, idField));
-		Log(LogDebug, "IdoPgsqlConnection", "saving contactnotification notification_id=" + Convert::ToString(static_cast<long>(GetSequenceValue(GetTablePrefix() + query.Table, idField))));
+		DbReference seqval = GetSequenceValue(GetTablePrefix() + query.Table, idField);
+		SetNotificationInsertID(query.NotificationObject, seqval);
+		Log(LogDebug, "IdoPgsqlConnection")
+		    << "saving contactnotification notification_id=" << Convert::ToString(seqval);
 	}
 }
 
diff --git a/lib/icinga/api.cpp b/lib/icinga/api.cpp
index 9e6afed7e..471d9324f 100644
--- a/lib/icinga/api.cpp
+++ b/lib/icinga/api.cpp
@@ -32,7 +32,8 @@ Value API::GetAnswerToEverything(const Dictionary::Ptr& params)
 	if (params)
 		text = params->Get("text");
 
-	Log(LogInformation, "API", "Hello from the Icinga 2 API: " + text);
+	Log(LogInformation, "API")
+	    << "Hello from the Icinga 2 API: " << text;
 
 	return 42;
 }
diff --git a/lib/icinga/checkable-check.cpp b/lib/icinga/checkable-check.cpp
index af37cead8..1290c1b34 100644
--- a/lib/icinga/checkable-check.cpp
+++ b/lib/icinga/checkable-check.cpp
@@ -417,11 +417,12 @@ void Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrig
 
 	olock.Unlock();
 
-//	Log(LogDebug, "Checkable", "Flapping: Checkable " + GetName() +
-//			" was: " + Convert::ToString(was_flapping) +
-//			" is: " + Convert::ToString(is_flapping) +
-//			" threshold: " + Convert::ToString(GetFlappingThreshold()) +
-//			"% current: " +	Convert::ToString(GetFlappingCurrent()) + "%.");
+//	Log(LogDebug, "Checkable")
+//	    << "Flapping: Checkable " << GetName()
+//	    << " was: " << (was_flapping)
+//	    << " is: " << is_flapping)
+//	    << " threshold: " << GetFlappingThreshold()
+//	    << "% current: " + GetFlappingCurrent()) << "%.";
 
 	OnNewCheckResult(GetSelf(), cr, origin);
 
@@ -433,10 +434,12 @@ void Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrig
 
 	if (hardChange) {
 		OnStateChange(GetSelf(), cr, StateTypeHard, origin);
-		Log(LogNotice, "Checkable", "State Change: Checkable " + GetName() + " hard state change from " + old_state_str + " to " + new_state_str + " detected.");
+		Log(LogNotice, "Checkable")
+		    << "State Change: Checkable " << GetName() << " hard state change from " << old_state_str << " to " << new_state_str << " detected.";
 	} else if (stateChange) {
 		OnStateChange(GetSelf(), cr, StateTypeSoft, origin);
-		Log(LogNotice, "Checkable", "State Change: Checkable " + GetName() + " soft state change from " + old_state_str + " to " + new_state_str + " detected.");
+		Log(LogNotice, "Checkable")
+		    << "State Change: Checkable " << GetName() << " soft state change from " << old_state_str << " to " << new_state_str << " detected.";
 	}
 
 	if (GetStateType() == StateTypeSoft || hardChange || recovery)
@@ -448,12 +451,14 @@ void Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrig
 	if (!was_flapping && is_flapping) {
 		OnNotificationsRequested(GetSelf(), NotificationFlappingStart, cr, "", "");
 
-		Log(LogNotice, "Checkable", "Flapping: Checkable " + GetName() + " started flapping (" + Convert::ToString(GetFlappingThreshold()) + "% < " + Convert::ToString(GetFlappingCurrent()) + "%).");
+		Log(LogNotice, "Checkable")
+		    << "Flapping: Checkable " << GetName() << " started flapping (" << GetFlappingThreshold() << "% < " << GetFlappingCurrent() << "%).";
 		OnFlappingChanged(GetSelf(), FlappingStarted);
 	} else if (was_flapping && !is_flapping) {
 		OnNotificationsRequested(GetSelf(), NotificationFlappingEnd, cr, "", "");
 
-		Log(LogNotice, "Checkable", "Flapping: Checkable " + GetName() + " stopped flapping (" + Convert::ToString(GetFlappingThreshold()) + "% >= " + Convert::ToString(GetFlappingCurrent()) + "%).");
+		Log(LogNotice, "Checkable")
+		    << "Flapping: Checkable " << GetName() << " stopped flapping (" << GetFlappingThreshold() << "% >= " << GetFlappingCurrent() << "%).";
 		OnFlappingChanged(GetSelf(), FlappingStopped);
 	} else if (send_notification)
 		OnNotificationsRequested(GetSelf(), recovery ? NotificationRecovery : NotificationProblem, cr, "", "");
diff --git a/lib/icinga/checkable-dependency.cpp b/lib/icinga/checkable-dependency.cpp
index d6e87133e..213031eb9 100644
--- a/lib/icinga/checkable-dependency.cpp
+++ b/lib/icinga/checkable-dependency.cpp
@@ -63,7 +63,8 @@ std::set<Dependency::Ptr> Checkable::GetReverseDependencies(void) const
 bool Checkable::IsReachable(DependencyType dt, Dependency::Ptr *failedDependency, int rstack) const
 {
 	if (rstack > 20) {
-		Log(LogWarning, "Checkable", "Too many nested dependencies for service '" + GetName() + "': Dependency failed.");
+		Log(LogWarning, "Checkable")
+		    << "Too many nested dependencies for service '" << GetName() << "': Dependency failed.";
 
 		return false;
 	}
diff --git a/lib/icinga/checkable-downtime.cpp b/lib/icinga/checkable-downtime.cpp
index 20207f02e..6bb640aff 100644
--- a/lib/icinga/checkable-downtime.cpp
+++ b/lib/icinga/checkable-downtime.cpp
@@ -104,8 +104,10 @@ String Checkable::AddDowntime(const String& author, const String& comment,
 		l_DowntimesCache[uid] = GetSelf();
 	}
 
-	Log(LogNotice, "Checkable", "Added downtime with ID '" + Convert::ToString(downtime->GetLegacyId()) +
-	    "' between '" + Utility::FormatDateTime("%Y-%m-%d %H:%M:%S", startTime) + "' and '" + Utility::FormatDateTime("%Y-%m-%d %H:%M:%S", endTime) + "'.");
+	Log(LogNotice, "Checkable")
+	    << "Added downtime with ID '" << downtime->GetLegacyId()
+	    << "' between '" << Utility::FormatDateTime("%Y-%m-%d %H:%M:%S", startTime)
+	    << "' and '" << Utility::FormatDateTime("%Y-%m-%d %H:%M:%S", endTime) << "'.";
 
 	OnDowntimeAdded(GetSelf(), downtime, origin);
 
@@ -131,7 +133,8 @@ void Checkable::RemoveDowntime(const String& id, bool cancelled, const MessageOr
 	String config_owner = downtime->GetConfigOwner();
 
 	if (!config_owner.IsEmpty()) {
-		Log(LogWarning, "Checkable", "Cannot remove downtime with ID '" + Convert::ToString(legacy_id) + "'. It is owned by scheduled downtime object '" + config_owner + "'");
+		Log(LogWarning, "Checkable")
+		    << "Cannot remove downtime with ID '" << legacy_id << "'. It is owned by scheduled downtime object '" << config_owner << "'";
 		return;
 	}
 
@@ -145,7 +148,8 @@ void Checkable::RemoveDowntime(const String& id, bool cancelled, const MessageOr
 
 	downtime->SetWasCancelled(cancelled);
 
-	Log(LogNotice, "Checkable", "Removed downtime with ID '" + Convert::ToString(downtime->GetLegacyId()) + "' from service '" + owner->GetName() + "'.");
+	Log(LogNotice, "Checkable")
+	    << "Removed downtime with ID '" << downtime->GetLegacyId() << "' from service '" << owner->GetName() << "'.";
 
 	OnDowntimeRemoved(owner, downtime, origin);
 }
@@ -178,16 +182,19 @@ void Checkable::TriggerDowntime(const String& id)
 		return;
 
 	if (downtime->IsActive() && downtime->IsTriggered()) {
-		Log(LogDebug, "Checkable", "Not triggering downtime with ID '" + Convert::ToString(downtime->GetLegacyId()) + "': already triggered.");
+		Log(LogDebug, "Checkable")
+		    << "Not triggering downtime with ID '" << downtime->GetLegacyId() << "': already triggered.";
 		return;
 	}
 
 	if (downtime->IsExpired()) {
-		Log(LogDebug, "Checkable", "Not triggering downtime with ID '" + Convert::ToString(downtime->GetLegacyId()) + "': expired.");
+		Log(LogDebug, "Checkable")
+		    << "Not triggering downtime with ID '" << downtime->GetLegacyId() << "': expired.";
 		return;
 	}
 
-	Log(LogNotice, "Checkable", "Triggering downtime with ID '" + Convert::ToString(downtime->GetLegacyId()) + "'.");
+	Log(LogNotice, "Checkable")
+		<< "Triggering downtime with ID '" << downtime->GetLegacyId() << "'.";
 
 	if (downtime->GetTriggerTime() == 0)
 		downtime->SetTriggerTime(Utility::GetTime());
diff --git a/lib/icinga/checkable-event.cpp b/lib/icinga/checkable-event.cpp
index afc9235e2..8ac20823c 100644
--- a/lib/icinga/checkable-event.cpp
+++ b/lib/icinga/checkable-event.cpp
@@ -75,7 +75,8 @@ void Checkable::ExecuteEventHandler(void)
 	if (!ec)
 		return;
 
-	Log(LogNotice, "Checkable", "Executing event handler '" + ec->GetName() + "' for service '" + GetName() + "'");
+	Log(LogNotice, "Checkable")
+	    << "Executing event handler '" << ec->GetName() << "' for service '" << GetName() << "'";
 
 	ec->Execute(GetSelf());
 
diff --git a/lib/icinga/checkable-flapping.cpp b/lib/icinga/checkable-flapping.cpp
index 70608aebd..fe3de9364 100644
--- a/lib/icinga/checkable-flapping.cpp
+++ b/lib/icinga/checkable-flapping.cpp
@@ -80,7 +80,8 @@ void Checkable::UpdateFlappingStatus(bool stateChange)
 	if (negative < 0)
 		negative = 0;
 
-//	Log(LogDebug, "Checkable", "Flapping counter for '" + GetName() + "' is positive=" + Convert::ToString(positive) + ", negative=" + Convert::ToString(negative));
+//	Log(LogDebug, "Checkable")
+//	    << "Flapping counter for '" << GetName() << "' is positive=" << positive << ", negative=" << negative;
 
 	SetFlappingLastChange(now);
 	SetFlappingPositive(positive);
diff --git a/lib/icinga/checkable-notification.cpp b/lib/icinga/checkable-notification.cpp
index 01ec04c91..cd255d843 100644
--- a/lib/icinga/checkable-notification.cpp
+++ b/lib/icinga/checkable-notification.cpp
@@ -51,32 +51,33 @@ void Checkable::SendNotifications(NotificationType type, const CheckResult::Ptr&
 
 	if (!IcingaApplication::GetInstance()->GetEnableNotifications() || !GetEnableNotifications()) {
 		if (!force) {
-			Log(LogInformation, "Checkable", "Notifications are disabled for service '" + GetName() + "'.");
+			Log(LogInformation, "Checkable")
+			    << "Notifications are disabled for service '" << GetName() << "'.";
 			return;
 		}
 
 		SetForceNextNotification(false);
 	}
 
-	Log(LogInformation, "Checkable", "Checking for configured notifications for object '" + GetName() + "'");
+	Log(LogInformation, "Checkable")
+	    << "Checking for configured notifications for object '" << GetName() << "'";
 
 	std::set<Notification::Ptr> notifications = GetNotifications();
 
 	if (notifications.empty())
-		Log(LogInformation, "Checkable", "Checkable '" + GetName() + "' does not have any notifications.");
+		Log(LogInformation, "Checkable")
+		    << "Checkable '" << GetName() << "' does not have any notifications.";
 
-	Log(LogDebug, "Checkable", "Checkable '" + GetName() + "' has " + Convert::ToString(notifications.size()) + " notification(s).");
+	Log(LogDebug, "Checkable")
+	    << "Checkable '" << GetName() << "' has " << notifications.size() << " notification(s).";
 
 	BOOST_FOREACH(const Notification::Ptr& notification, notifications) {
 		try {
 			notification->BeginExecuteNotification(type, cr, force, author, text);
 		} catch (const std::exception& ex) {
-			std::ostringstream msgbuf;
-			msgbuf << "Exception occured during notification for service '"
-			       << GetName() << "': " << DiagnosticInformation(ex);
-			String message = msgbuf.str();
-
-			Log(LogWarning, "Checkable", message);
+			Log(LogWarning, "Checkable")
+			    << "Exception occured during notification for service '"
+			    << GetName() << "': " << DiagnosticInformation(ex);
 		}
 	}
 }
diff --git a/lib/icinga/dependency-apply.cpp b/lib/icinga/dependency-apply.cpp
index 9133bc5c4..5e5695582 100644
--- a/lib/icinga/dependency-apply.cpp
+++ b/lib/icinga/dependency-apply.cpp
@@ -62,9 +62,8 @@ bool Dependency::EvaluateApplyRuleOne(const Checkable::Ptr& checkable, const App
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Applying dependency '" << rule.GetName() << "' to object '" << checkable->GetName() << "' for rule " << di;
-	Log(LogDebug, "Dependency", msgbuf2.str());
+	Log(LogDebug, "Dependency")
+	    << "Applying dependency '" << rule.GetName() << "' to object '" << checkable->GetName() << "' for rule " << di;
 
 	ConfigItemBuilder::Ptr builder = make_shared<ConfigItemBuilder>(di);
 	builder->SetType("Dependency");
@@ -127,7 +126,8 @@ void Dependency::EvaluateApplyRule(const ApplyRule& rule)
 		}
 
 		if (apply_count == 0)
-			Log(LogWarning, "Dependency", "Apply rule '" + rule.GetName() + "' for host does not match anywhere!");
+			Log(LogWarning, "Dependency")
+			    << "Apply rule '" << rule.GetName() << "' for host does not match anywhere!";
 
 	} else if (rule.GetTargetType() == "Service") {
 		apply_count = 0;
@@ -145,10 +145,12 @@ void Dependency::EvaluateApplyRule(const ApplyRule& rule)
 		}
 
 		if (apply_count == 0)
-			Log(LogWarning, "Dependency", "Apply rule '" + rule.GetName() + "' for service does not match anywhere!");
+			Log(LogWarning, "Dependency")
+			    << "Apply rule '" << rule.GetName() << "' for service does not match anywhere!";
 
 	} else {
-		Log(LogWarning, "Dependency", "Wrong target type for apply rule '" + rule.GetName() + "'!");
+		Log(LogWarning, "Dependency")
+		    << "Wrong target type for apply rule '" << rule.GetName() << "'!";
 	}
 }
 
diff --git a/lib/icinga/dependency.cpp b/lib/icinga/dependency.cpp
index 3b3826177..09310e0bc 100644
--- a/lib/icinga/dependency.cpp
+++ b/lib/icinga/dependency.cpp
@@ -66,16 +66,19 @@ void Dependency::OnStateLoaded(void)
 
 	if (childHost) {
 		if (GetChildServiceName().IsEmpty()) {
-			Log(LogDebug, "Dependency", "Dependency '" + GetName() + "' child host '" + GetChildHostName() + ".");
+			Log(LogDebug, "Dependency")
+			    << "Dependency '" << GetName() << "' child host '" << GetChildHostName() << ".";
 			m_Child = childHost;
 		} else {
-			Log(LogDebug, "Dependency", "Dependency '" + GetName() + "' child host '" + GetChildHostName() + "' service '" + GetChildServiceName() + "' .");
+			Log(LogDebug, "Dependency")
+			    << "Dependency '" << GetName() << "' child host '" << GetChildHostName() << "' service '" << GetChildServiceName() << "' .";
 			m_Child = childHost->GetServiceByShortName(GetChildServiceName());
 		}
 	}
 	
 	if (!m_Child)
-		Log(LogWarning, "Dependency", "Dependency '" + GetName() + "' references an invalid child object and will be ignored.");
+		Log(LogWarning, "Dependency")
+		    << "Dependency '" << GetName() << "' references an invalid child object and will be ignored.";
 	else
 		m_Child->AddDependency(GetSelf());
 
@@ -83,16 +86,19 @@ void Dependency::OnStateLoaded(void)
 
 	if (parentHost) {
 		if (GetParentServiceName().IsEmpty()) {
-			Log(LogDebug, "Dependency", "Dependency '" + GetName() + "' parent host '" + GetParentHostName() + ".");
+			Log(LogDebug, "Dependency")
+			    << "Dependency '" << GetName() << "' parent host '" << GetParentHostName() << ".";
 			m_Parent = parentHost;
 		} else {
-			Log(LogDebug, "Dependency", "Dependency '" + GetName() + "' parent host '" + GetParentHostName() + "' service '" + GetParentServiceName() + "' .");
+			Log(LogDebug, "Dependency")
+			    << "Dependency '" << GetName() << "' parent host '" << GetParentHostName() << "' service '" << GetParentServiceName() << "' .";
 			m_Parent = parentHost->GetServiceByShortName(GetParentServiceName());
 		}
 	}
 	
 	if (!m_Parent)
-		Log(LogWarning, "Dependency", "Dependency '" + GetName() + "' references an invalid parent object and will always fail.");
+		Log(LogWarning, "Dependency")
+		    << "Dependency '" << GetName() << "' references an invalid parent object and will always fail.";
 	else
 		m_Parent->AddReverseDependency(GetSelf());
 }
@@ -121,19 +127,22 @@ bool Dependency::IsAvailable(DependencyType dt) const
 
 	/* ignore if it's the same checkable object */
 	if (parent == GetChild()) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: Parent and child " + (service ? "service" : "host") + " are identical.");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: Parent and child " << (service ? "service" : "host") << " are identical.";
 		return true;
 	}
 
 	/* ignore pending  */
 	if (!parent->GetLastCheckResult()) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: " + (service ? "Service" : "Host") + " '" + parent->GetName() + "' hasn't been checked yet.");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: " << (service ? "Service" : "Host") << " '" << parent->GetName() << "' hasn't been checked yet.";
 		return true;
 	}
 
 	/* ignore soft states */
 	if (parent->GetStateType() == StateTypeSoft) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: " + (service ? "Service" : "Host") + " '" + parent->GetName() + "' is in a soft state.");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: " << (service ? "Service" : "Host") << " '" << parent->GetName() << "' is in a soft state.";
 		return true;
 	}
 
@@ -146,28 +155,34 @@ bool Dependency::IsAvailable(DependencyType dt) const
 
 	/* check state */
 	if (state & GetStateFilter()) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: " + (service ? "Service" : "Host") + " '" + parent->GetName() + "' matches state filter.");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: " << (service ? "Service" : "Host") << " '" << parent->GetName() << "' matches state filter.";
 		return true;
 	}
 
 	/* ignore if not in time period */
 	TimePeriod::Ptr tp = GetPeriod();
 	if (tp && !tp->IsInside(Utility::GetTime())) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: Outside time period.");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: Outside time period.";
 		return true;
 	}
 
 	if (dt == DependencyCheckExecution && !GetDisableChecks()) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: Checks are not disabled.");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: Checks are not disabled.";
 		return true;
 	} else if (dt == DependencyNotification && !GetDisableNotifications()) {
-		Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' passed: Notifications are not disabled");
+		Log(LogNotice, "Dependency")
+		    << "Dependency '" << GetName() << "' passed: Notifications are not disabled";
 		return true;
 	}
 
-	Log(LogNotice, "Dependency", "Dependency '" + GetName() + "' failed. Parent " +
-		(service ? "service" : "host") + " '" + parent->GetName() + "' is " +
-		(service ? Service::StateToString(service->GetState()) : Host::StateToString(host->GetState())));
+	Log(LogNotice, "Dependency")
+	    << "Dependency '" << GetName() << "' failed. Parent "
+	    << (service ? "service" : "host") << " '" << parent->GetName() << "' is "
+	    << (service ? Service::StateToString(service->GetState()) : Host::StateToString(host->GetState()));
+
 	return false;
 }
 
diff --git a/lib/icinga/hostgroup.cpp b/lib/icinga/hostgroup.cpp
index 8c2ccae1f..8c8482ab1 100644
--- a/lib/icinga/hostgroup.cpp
+++ b/lib/icinga/hostgroup.cpp
@@ -51,15 +51,15 @@ bool HostGroup::EvaluateObjectRuleOne(const Host::Ptr& host, const ObjectRule& r
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Assigning membership for group '" << rule.GetName() << "' to host '" << host->GetName() << "' for rule " << di;
-	Log(LogDebug, "HostGroup", msgbuf2.str());
+	Log(LogDebug, "HostGroup")
+	    << "Assigning membership for group '" << rule.GetName() << "' to host '" << host->GetName() << "' for rule " << di;
 
 	String group_name = rule.GetName();
 	HostGroup::Ptr group = HostGroup::GetByName(group_name);
 
 	if (!group) {
-		Log(LogCritical, "HostGroup", "Invalid membership assignment. Group '" + group_name + "' does not exist.");
+		Log(LogCritical, "HostGroup")
+		    << "Invalid membership assignment. Group '" << group_name << "' does not exist.";
 		return false;
 	}
 
@@ -113,8 +113,9 @@ void HostGroup::RemoveMember(const Host::Ptr& host)
 bool HostGroup::ResolveGroupMembership(Host::Ptr const& host, bool add, int rstack) {
 
 	if (add && rstack > 20) {
-		Log(LogWarning, "HostGroup", "Too many nested groups for group '" + GetName() + "': Host '" +
-		    host->GetName() + "' membership assignment failed.");
+		Log(LogWarning, "HostGroup")
+		    << "Too many nested groups for group '" << GetName() << "': Host '"
+		    << host->GetName() << "' membership assignment failed.";
 
 		return false;
 	}
diff --git a/lib/icinga/legacytimeperiod.cpp b/lib/icinga/legacytimeperiod.cpp
index fc87ae660..edacace87 100644
--- a/lib/icinga/legacytimeperiod.cpp
+++ b/lib/icinga/legacytimeperiod.cpp
@@ -323,7 +323,9 @@ bool LegacyTimePeriod::IsInDayDefinition(const String& daydef, tm *reference)
 
 	ParseTimeRange(daydef, &begin, &end, &stride, reference);
 
-	Log(LogDebug, "LegacyTimePeriod", "ParseTimeRange: '" + daydef + "' => " + Convert::ToString(static_cast<long>(mktime(&begin))) + " -> " + Convert::ToString(static_cast<long>(mktime(&end))) + ", stride: " + Convert::ToString(stride));
+	Log(LogDebug, "LegacyTimePeriod")
+	    << "ParseTimeRange: '" << daydef << "' => " << mktime(&begin)
+	    << " -> " << mktime(&end) << ", stride: " << stride;
 
 	return IsInTimeRange(&begin, &end, stride, reference);
 }
@@ -451,20 +453,23 @@ Array::Ptr LegacyTimePeriod::ScriptFunc(const TimePeriod::Ptr& tp, double begin,
 			tm reference = Utility::LocalTime(refts);
 
 #ifdef _DEBUG
-			Log(LogDebug, "LegacyTimePeriod", "Checking reference time " + Convert::ToString(static_cast<long>(refts)));
+			Log(LogDebug, "LegacyTimePeriod")
+			    << "Checking reference time " << refts;
 #endif /* _DEBUG */
 
 			ObjectLock olock(ranges);
 			BOOST_FOREACH(const Dictionary::Pair& kv, ranges) {
 				if (!IsInDayDefinition(kv.first, &reference)) {
 #ifdef _DEBUG
-					Log(LogDebug, "LegacyTimePeriod", "Not in day definition '" + kv.first + "'.");
+					Log(LogDebug, "LegacyTimePeriod")
+					    << "Not in day definition '" << kv.first << "'.";
 #endif /* _DEBUG */
 					continue;
 				}
 
 #ifdef _DEBUG
-				Log(LogDebug, "LegacyTimePeriod", "In day definition '" + kv.first + "'.");
+				Log(LogDebug, "LegacyTimePeriod")
+				    << "In day definition '" << kv.first << "'.";
 #endif /* _DEBUG */
 
 				ProcessTimeRanges(kv.second, &reference, segments);
@@ -472,7 +477,8 @@ Array::Ptr LegacyTimePeriod::ScriptFunc(const TimePeriod::Ptr& tp, double begin,
 		}
 	}
 
-	Log(LogDebug, "LegacyTimePeriod", "Legacy timeperiod update returned " + Convert::ToString(static_cast<long>(segments->GetLength())) + " segments.");
+	Log(LogDebug, "LegacyTimePeriod")
+	    << "Legacy timeperiod update returned " << segments->GetLength() << " segments.";
 
 	return segments;
 }
diff --git a/lib/icinga/macroprocessor.cpp b/lib/icinga/macroprocessor.cpp
index 09c04ba2b..a0e63c9da 100644
--- a/lib/icinga/macroprocessor.cpp
+++ b/lib/icinga/macroprocessor.cpp
@@ -183,7 +183,8 @@ String MacroProcessor::InternalResolveMacros(const String& str, const ResolverLi
 
 		if (!found) {
 			if (!missingMacro)
-				Log(LogWarning, "MacroProcessor", "Macro '" + name + "' is not defined.");
+				Log(LogWarning, "MacroProcessor")
+				    << "Macro '" << name << "' is not defined.";
 			else
 				*missingMacro = name;
 		}
diff --git a/lib/icinga/notification-apply.cpp b/lib/icinga/notification-apply.cpp
index 3c0b64ed6..bb1e560be 100644
--- a/lib/icinga/notification-apply.cpp
+++ b/lib/icinga/notification-apply.cpp
@@ -62,9 +62,8 @@ bool Notification::EvaluateApplyRuleOne(const Checkable::Ptr& checkable, const A
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Applying notification '" << rule.GetName() << "' to object '" << checkable->GetName() << "' for rule " << di;
-	Log(LogDebug, "Notification", msgbuf2.str());
+	Log(LogDebug, "Notification")
+	    << "Applying notification '" << rule.GetName() << "' to object '" << checkable->GetName() << "' for rule " << di;
 
 	ConfigItemBuilder::Ptr builder = make_shared<ConfigItemBuilder>(di);
 	builder->SetType("Notification");
@@ -122,7 +121,8 @@ void Notification::EvaluateApplyRule(const ApplyRule& rule)
 		}
 
 		if (apply_count == 0)
-			Log(LogWarning, "Notification", "Apply rule '" + rule.GetName() + "' for host does not match anywhere!");
+			Log(LogWarning, "Notification")
+			    << "Apply rule '" << rule.GetName() << "' for host does not match anywhere!";
 
 	} else if (rule.GetTargetType() == "Service") {
 		apply_count = 0;
@@ -140,10 +140,12 @@ void Notification::EvaluateApplyRule(const ApplyRule& rule)
 		}
 
 		if (apply_count == 0)
-			Log(LogWarning, "Notification", "Apply rule '" + rule.GetName() + "' for service does not match anywhere!");
+			Log(LogWarning, "Notification")
+			    << "Apply rule '" << rule.GetName() << "' for service does not match anywhere!";
 
 	} else {
-		Log(LogWarning, "Notification", "Wrong target type for apply rule '" + rule.GetName() + "'!");
+		Log(LogWarning, "Notification")
+		    << "Wrong target type for apply rule '" << rule.GetName() << "'!";
 	}
 }
 void Notification::EvaluateApplyRules(const std::vector<ApplyRule>& rules)
diff --git a/lib/icinga/notification.cpp b/lib/icinga/notification.cpp
index 1031c2884..c7602b688 100644
--- a/lib/icinga/notification.cpp
+++ b/lib/icinga/notification.cpp
@@ -231,7 +231,8 @@ void Notification::BeginExecuteNotification(NotificationType type, const CheckRe
 		TimePeriod::Ptr tp = GetPeriod();
 
 		if (tp && !tp->IsInside(Utility::GetTime())) {
-			Log(LogNotice, "Notification", "Not sending notifications for notification object '" + GetName() + "': not in timeperiod");
+			Log(LogNotice, "Notification")
+			    << "Not sending notifications for notification object '" << GetName() << "': not in timeperiod";
 			return;
 		}
 
@@ -240,22 +241,26 @@ void Notification::BeginExecuteNotification(NotificationType type, const CheckRe
 
 		if (type == NotificationProblem) {
 			if (times && times->Contains("begin") && now < checkable->GetLastHardStateChange() + times->Get("begin")) {
-				Log(LogNotice, "Notification", "Not sending notifications for notification object '" + GetName() + "': before escalation range");
+				Log(LogNotice, "Notification")
+				    << "Not sending notifications for notification object '" << GetName() << "': before escalation range";
 				return;
 			}
 
 			if (times && times->Contains("end") && now > checkable->GetLastHardStateChange() + times->Get("end")) {
-				Log(LogNotice, "Notification", "Not sending notifications for notification object '" + GetName() + "': after escalation range");
+				Log(LogNotice, "Notification")
+				    << "Not sending notifications for notification object '" << GetName() << "': after escalation range";
 				return;
 			}
 		}
 
 		unsigned long ftype = 1 << type;
 
-		Log(LogDebug, "Notification", "FType=" + Convert::ToString(ftype) + ", TypeFilter=" + Convert::ToString(GetTypeFilter()));
+		Log(LogDebug, "Notification")
+		    << "FType=" << ftype << ", TypeFilter=" << GetTypeFilter();
 
 		if (!(ftype & GetTypeFilter())) {
-			Log(LogNotice, "Notification", "Not sending notifications for notification object '" + GetName() + "': type filter does not match");
+			Log(LogNotice, "Notification")
+			    << "Not sending notifications for notification object '" << GetName() << "': type filter does not match";
 			return;
 		}
 
@@ -271,7 +276,8 @@ void Notification::BeginExecuteNotification(NotificationType type, const CheckRe
 			fstate = HostStateToFilter(host->GetState());
 
 		if (!(fstate & GetStateFilter())) {
-			Log(LogNotice, "Notification", "Not sending notifications for notification object '" + GetName() + "': state filter does not match");
+			Log(LogNotice, "Notification")
+			    << "Not sending notifications for notification object '" << GetName() << "': state filter does not match";
 			return;
 		}
 	}
@@ -303,7 +309,9 @@ void Notification::BeginExecuteNotification(NotificationType type, const CheckRe
 		if (!user->GetEnableNotifications() || !CheckNotificationUserFilters(type, user, force))
 			continue;
 
-		Log(LogInformation, "Notification", "Sending notification for user '" + user->GetName() + "'");
+		Log(LogInformation, "Notification")
+		    << "Sending notification for user '" << user->GetName() << "'";
+
 		Utility::QueueAsyncCallback(boost::bind(&Notification::ExecuteNotificationHelper, this, type, user, cr, force, author, text));
 
 		/* collect all notified users */
@@ -322,16 +330,18 @@ bool Notification::CheckNotificationUserFilters(NotificationType type, const Use
 		TimePeriod::Ptr tp = user->GetPeriod();
 
 		if (tp && !tp->IsInside(Utility::GetTime())) {
-			Log(LogNotice, "Notification", "Not sending notifications for notification object '" +
-			    GetName() + " and user '" + user->GetName() + "': user not in timeperiod");
+			Log(LogNotice, "Notification")
+			    << "Not sending notifications for notification object '"
+			    << GetName() << " and user '" << user->GetName() << "': user not in timeperiod";
 			return false;
 		}
 
 		unsigned long ftype = 1 << type;
 
 		if (!(ftype & user->GetTypeFilter())) {
-			Log(LogNotice, "Notification", "Not sending notifications for notification object '" +
-			    GetName() + " and user '" + user->GetName() + "': type filter does not match");
+			Log(LogNotice, "Notification")
+			    << "Not sending notifications for notification object '"
+			    << GetName() << " and user '" << user->GetName() << "': type filter does not match";
 			return false;
 		}
 
@@ -348,8 +358,9 @@ bool Notification::CheckNotificationUserFilters(NotificationType type, const Use
 				fstate = HostStateToFilter(host->GetState());
 
 		if (!(fstate & user->GetStateFilter())) {
-			Log(LogNotice, "Notification", "Not sending notifications for notification object '" +
-			    GetName() + " and user '" + user->GetName() + "': state filter does not match");
+			Log(LogNotice, "Notification")
+			    << "Not sending notifications for notification object '"
+			    << GetName() << " and user '" << user->GetName() << "': state filter does not match";
 			return false;
 		}
 	}
@@ -365,7 +376,8 @@ void Notification::ExecuteNotificationHelper(NotificationType type, const User::
 		NotificationCommand::Ptr command = GetCommand();
 
 		if (!command) {
-			Log(LogDebug, "Notification", "No notification_command found for notification '" + GetName() + "'. Skipping execution.");
+			Log(LogDebug, "Notification")
+			    << "No notification_command found for notification '" << GetName() << "'. Skipping execution.";
 			return;
 		}
 
@@ -380,12 +392,12 @@ void Notification::ExecuteNotificationHelper(NotificationType type, const User::
 		/* required by compatlogger */
 		Service::OnNotificationSentToUser(GetSelf(), GetCheckable(), user, type, cr, author, text, command->GetName());
 
-		Log(LogInformation, "Notification", "Completed sending notification for object '" + GetCheckable()->GetName() + "'");
+		Log(LogInformation, "Notification")
+		    << "Completed sending notification for object '" << GetCheckable()->GetName() << "'";
 	} catch (const std::exception& ex) {
-		std::ostringstream msgbuf;
-		msgbuf << "Exception occured during notification for object '"
-		       << GetCheckable()->GetName() << "': " << DiagnosticInformation(ex);
-		Log(LogWarning, "Notification", msgbuf.str());
+		Log(LogWarning, "Notification")
+		    << "Exception occured during notification for object '"
+		    << GetCheckable()->GetName() << "': " << DiagnosticInformation(ex);
 	}
 }
 
diff --git a/lib/icinga/pluginutility.cpp b/lib/icinga/pluginutility.cpp
index 4ad707db8..55e9f028a 100644
--- a/lib/icinga/pluginutility.cpp
+++ b/lib/icinga/pluginutility.cpp
@@ -102,7 +102,8 @@ void PluginUtility::ExecuteCommand(const Command::Ptr& commandObj, const Checkab
 							continue;
 					} catch (const std::exception& ex) {
 						/* tried to convert a string */
-						Log(LogWarning, "PluginUtility", "Error evaluating set_if value '" + set_if_resolved + "': " + ex.what());
+						Log(LogWarning, "PluginUtility")
+						    << "Error evaluating set_if value '" << set_if_resolved << "': " << ex.what();
 						continue;
 					}
 				}
diff --git a/lib/icinga/scheduleddowntime-apply.cpp b/lib/icinga/scheduleddowntime-apply.cpp
index 172153376..22ca00ad3 100644
--- a/lib/icinga/scheduleddowntime-apply.cpp
+++ b/lib/icinga/scheduleddowntime-apply.cpp
@@ -61,9 +61,8 @@ bool ScheduledDowntime::EvaluateApplyRule(const Checkable::Ptr& checkable, const
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Applying scheduled downtime '" << rule.GetName() << "' to object '" << checkable->GetName() << "' for rule " << di;
-	Log(LogDebug, "ScheduledDowntime", msgbuf2.str());
+	Log(LogDebug, "ScheduledDowntime")
+	    << "Applying scheduled downtime '" << rule.GetName() << "' to object '" << checkable->GetName() << "' for rule " << di;
 
 	ConfigItemBuilder::Ptr builder = make_shared<ConfigItemBuilder>(di);
 	builder->SetType("ScheduledDowntime");
@@ -122,7 +121,8 @@ void ScheduledDowntime::EvaluateApplyRules(const std::vector<ApplyRule>& rules)
 			}
 
 			if (apply_count == 0)
-				Log(LogWarning, "ScheduledDowntime", "Apply rule '" + rule.GetName() + "' for host does not match anywhere!");
+				Log(LogWarning, "ScheduledDowntime")
+				    << "Apply rule '" << rule.GetName() << "' for host does not match anywhere!";
 
 		} else if (rule.GetTargetType() == "Service") {
 			apply_count = 0;
@@ -140,10 +140,12 @@ void ScheduledDowntime::EvaluateApplyRules(const std::vector<ApplyRule>& rules)
 			}
 
 			if (apply_count == 0)
-				Log(LogWarning, "ScheduledDowntime", "Apply rule '" + rule.GetName() + "' for service does not match anywhere!");
+				Log(LogWarning, "ScheduledDowntime")
+				    << "Apply rule '" << rule.GetName() << "' for service does not match anywhere!";
 
 		} else {
-			Log(LogWarning, "ScheduledDowntime", "Wrong target type for apply rule '" + rule.GetName() + "'!");
+			Log(LogWarning, "ScheduledDowntime")
+			    << "Wrong target type for apply rule '" << rule.GetName() << "'!";
 		}
 	}
 }
diff --git a/lib/icinga/scheduleddowntime.cpp b/lib/icinga/scheduleddowntime.cpp
index fa7722075..34f6582f5 100644
--- a/lib/icinga/scheduleddowntime.cpp
+++ b/lib/icinga/scheduleddowntime.cpp
@@ -91,7 +91,8 @@ std::pair<double, double> ScheduledDowntime::FindNextSegment(void)
 	time_t refts = Utility::GetTime();
 	tm reference = Utility::LocalTime(refts);
 
-	Log(LogDebug, "ScheduledDowntime", "Finding next scheduled downtime segment for time " + Convert::ToString(static_cast<long>(refts)));
+	Log(LogDebug, "ScheduledDowntime")
+	    << "Finding next scheduled downtime segment for time " << refts;
 
 	Dictionary::Ptr ranges = GetRanges();
 
diff --git a/lib/icinga/service-apply.cpp b/lib/icinga/service-apply.cpp
index 9ba215dbb..3312b6a23 100644
--- a/lib/icinga/service-apply.cpp
+++ b/lib/icinga/service-apply.cpp
@@ -54,9 +54,8 @@ bool Service::EvaluateApplyRuleOne(const Host::Ptr& host, const ApplyRule& rule)
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Applying service '" << rule.GetName() << "' to host '" << host->GetName() << "' for rule " << di;
-	Log(LogDebug, "Service", msgbuf2.str());
+	Log(LogDebug, "Service")
+	    << "Applying service '" << rule.GetName() << "' to host '" << host->GetName() << "' for rule " << di;
 
 	ConfigItemBuilder::Ptr builder = make_shared<ConfigItemBuilder>(di);
 	builder->SetType("Service");
@@ -109,7 +108,8 @@ void Service::EvaluateApplyRule(const ApplyRule& rule)
 	}
 
 	if (apply_count == 0)
-		Log(LogWarning, "Service", "Apply rule '" + rule.GetName() + "' for host does not match anywhere!");
+		Log(LogWarning, "Service")
+		    << "Apply rule '" << rule.GetName() << "' for host does not match anywhere!";
 }
 
 void Service::EvaluateApplyRules(const std::vector<ApplyRule>& rules)
diff --git a/lib/icinga/servicegroup.cpp b/lib/icinga/servicegroup.cpp
index be8daa389..76aa92833 100644
--- a/lib/icinga/servicegroup.cpp
+++ b/lib/icinga/servicegroup.cpp
@@ -54,15 +54,15 @@ bool ServiceGroup::EvaluateObjectRuleOne(const Service::Ptr& service, const Obje
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Assigning membership for group '" << rule.GetName() << "' to service '" << service->GetName() << "' for rule " << di;
-	Log(LogDebug, "ServiceGroup", msgbuf2.str());
+	Log(LogDebug, "ServiceGroup")
+	    << "Assigning membership for group '" << rule.GetName() << "' to service '" << service->GetName() << "' for rule " << di;
 
 	String group_name = rule.GetName();
 	ServiceGroup::Ptr group = ServiceGroup::GetByName(group_name);
 
 	if (!group) {
-		Log(LogCritical, "ServiceGroup", "Invalid membership assignment. Group '" + group_name + "' does not exist.");
+		Log(LogCritical, "ServiceGroup")
+		    << "Invalid membership assignment. Group '" << group_name << "' does not exist.";
 		return false;
 	}
 
@@ -116,8 +116,9 @@ void ServiceGroup::RemoveMember(const Service::Ptr& service)
 bool ServiceGroup::ResolveGroupMembership(Service::Ptr const& service, bool add, int rstack) {
 
 	if (add && rstack > 20) {
-		Log(LogWarning, "ServiceGroup", "Too many nested groups for group '" + GetName() + "': Service '" +
-		    service->GetName() + "' membership assignment failed.");
+		Log(LogWarning, "ServiceGroup")
+		    << "Too many nested groups for group '" << GetName() << "': Service '"
+		    << service->GetName() << "' membership assignment failed.";
 
 		return false;
 	}
diff --git a/lib/icinga/timeperiod.cpp b/lib/icinga/timeperiod.cpp
index 292373a52..929249b63 100644
--- a/lib/icinga/timeperiod.cpp
+++ b/lib/icinga/timeperiod.cpp
@@ -55,7 +55,9 @@ void TimePeriod::AddSegment(double begin, double end)
 {
 	ASSERT(OwnsLock());
 
-	Log(LogDebug, "TimePeriod", "Adding segment '" + Utility::FormatDateTime("%c", begin) + "' <-> '" + Utility::FormatDateTime("%c", end) + "' to TimePeriod '" + GetName() + "'");
+	Log(LogDebug, "TimePeriod")
+	    << "Adding segment '" << Utility::FormatDateTime("%c", begin) << "' <-> '"
+	    << Utility::FormatDateTime("%c", end) << "' to TimePeriod '" << GetName() << "'";
 
 	if (GetValidBegin().IsEmpty() || begin < GetValidBegin())
 		SetValidBegin(begin);
@@ -106,7 +108,9 @@ void TimePeriod::RemoveSegment(double begin, double end)
 {
 	ASSERT(OwnsLock());
 
-	Log(LogDebug, "TimePeriod", "Removing segment '" + Utility::FormatDateTime("%c", begin) + "' <-> '" + Utility::FormatDateTime("%c", end) + "' from TimePeriod '" + GetName() + "'");
+	Log(LogDebug, "TimePeriod")
+	    << "Removing segment '" << Utility::FormatDateTime("%c", begin) << "' <-> '"
+	    << Utility::FormatDateTime("%c", end) << "' from TimePeriod '" << GetName() << "'";
 
 	if (GetValidBegin().IsEmpty() || begin < GetValidBegin())
 		SetValidBegin(begin);
@@ -154,7 +158,9 @@ void TimePeriod::PurgeSegments(double end)
 {
 	ASSERT(OwnsLock());
 
-	Log(LogDebug, "TimePeriod", "Purging segments older than '" + Utility::FormatDateTime("%c", end) + "' from TimePeriod '" + GetName() + "'");
+	Log(LogDebug, "TimePeriod")
+	    << "Purging segments older than '" << Utility::FormatDateTime("%c", end)
+	    << "' from TimePeriod '" << GetName() << "'";
 
 	if (GetValidBegin().IsEmpty() || end < GetValidBegin())
 		return;
@@ -275,15 +281,19 @@ void TimePeriod::Dump(void)
 {
 	Array::Ptr segments = GetSegments();
 
-	Log(LogDebug, "TimePeriod", "Dumping TimePeriod '" + GetName() + "'");
-	Log(LogDebug, "TimePeriod", "Valid from '" + Utility::FormatDateTime("%c", GetValidBegin()) + "' until '" + Utility::FormatDateTime("%c", GetValidEnd()));
+	Log(LogDebug, "TimePeriod")
+	    << "Dumping TimePeriod '" << GetName() << "'";
+
+	Log(LogDebug, "TimePeriod")
+	    << "Valid from '" << Utility::FormatDateTime("%c", GetValidBegin())
+	    << "' until '" << Utility::FormatDateTime("%c", GetValidEnd());
 
 	if (segments) {
 		ObjectLock dlock(segments);
 		BOOST_FOREACH(const Dictionary::Ptr& segment, segments) {
-			Log(LogDebug, "TimePeriod", "Segment: " +
-			    Utility::FormatDateTime("%c", segment->Get("begin")) + " <-> " +
-			    Utility::FormatDateTime("%c", segment->Get("end")));
+			Log(LogDebug, "TimePeriod")
+			    << "Segment: " << Utility::FormatDateTime("%c", segment->Get("begin")) << " <-> "
+			    << Utility::FormatDateTime("%c", segment->Get("end"));
 		}
 	}
 
diff --git a/lib/icinga/usergroup.cpp b/lib/icinga/usergroup.cpp
index c17a0b622..4bfa70bd2 100644
--- a/lib/icinga/usergroup.cpp
+++ b/lib/icinga/usergroup.cpp
@@ -51,15 +51,15 @@ bool UserGroup::EvaluateObjectRuleOne(const User::Ptr& user, const ObjectRule& r
 	if (!rule.EvaluateFilter(locals))
 		return false;
 
-	std::ostringstream msgbuf2;
-	msgbuf2 << "Assigning membership for group '" << rule.GetName() << "' to user '" << user->GetName() << "' for rule " << di;
-	Log(LogDebug, "UserGroup", msgbuf2.str());
+	Log(LogDebug, "UserGroup")
+	    << "Assigning membership for group '" << rule.GetName() << "' to user '" << user->GetName() << "' for rule " << di;
 
 	String group_name = rule.GetName();
 	UserGroup::Ptr group = UserGroup::GetByName(group_name);
 
 	if (!group) {
-		Log(LogCritical, "UserGroup", "Invalid membership assignment. Group '" + group_name + "' does not exist.");
+		Log(LogCritical, "UserGroup")
+		    << "Invalid membership assignment. Group '" << group_name << "' does not exist.";
 		return false;
 	}
 
@@ -113,8 +113,9 @@ void UserGroup::RemoveMember(const User::Ptr& user)
 bool UserGroup::ResolveGroupMembership(User::Ptr const& user, bool add, int rstack) {
 
 	if (add && rstack > 20) {
-		Log(LogWarning, "UserGroup", "Too many nested groups for group '" + GetName() + "': User '" +
-		    user->GetName() + "' membership assignment failed.");
+		Log(LogWarning, "UserGroup")
+		    << "Too many nested groups for group '" << GetName() << "': User '"
+		    << user->GetName() << "' membership assignment failed.";
 
 		return false;
 	}
diff --git a/lib/livestatus/attributefilter.cpp b/lib/livestatus/attributefilter.cpp
index a62c2ae99..6260afef1 100644
--- a/lib/livestatus/attributefilter.cpp
+++ b/lib/livestatus/attributefilter.cpp
@@ -69,12 +69,14 @@ bool AttributeFilter::Apply(const Table::Ptr& table, const Value& row)
 				boost::smatch what;
 				ret = boost::regex_search(operand.GetData(), what, expr);
 			} catch (boost::exception&) {
-				Log(LogWarning, "AttributeFilter", "Regex '" + m_Operand + " " + m_Operator + " " + Convert::ToString(value) + "' error.");
+				Log(LogWarning, "AttributeFilter")
+				    << "Regex '" << m_Operand << " " << m_Operator << " " << value << "' error.";
 				ret = false;
 			}
 
-			//Log(LogDebug, "LivestatusListener/AttributeFilter", "Attribute filter '" + m_Operand + " " + m_Operator + " " +
-			//    static_cast<String>(value) + "' " + (ret ? "matches" : "doesn't match") + "." );
+			//Log(LogDebug, "LivestatusListener/AttributeFilter")
+			//    << "Attribute filter '" << m_Operand + " " << m_Operator << " "
+			//    << value << "' " << (ret ? "matches" : "doesn't match") << ".";
 
 			return ret;
 		} else if (m_Operator == "=~") {
@@ -87,12 +89,14 @@ bool AttributeFilter::Apply(const Table::Ptr& table, const Value& row)
 				boost::smatch what;
 				ret = boost::regex_search(operand.GetData(), what, expr);
 			} catch (boost::exception&) {
-				Log(LogWarning, "AttributeFilter", "Regex '" + m_Operand + " " + m_Operator + " " + Convert::ToString(value) + "' error.");
+				Log(LogWarning, "AttributeFilter")
+				    << "Regex '" << m_Operand << " " << m_Operator << " " << value << "' error.";
 				ret = false;
 			}
 
-			//Log(LogDebug, "LivestatusListener/AttributeFilter", "Attribute filter '" + m_Operand + " " + m_Operator + " " +
-			//    static_cast<String>(value) + "' " + (ret ? "matches" : "doesn't match") + "." );
+			//Log(LogDebug, "LivestatusListener/AttributeFilter")
+			//    << "Attribute filter '" << m_Operand << " " << m_Operator << " "
+			//    << value << "' " << (ret ? "matches" : "doesn't match") << ".";
 
 			return ret;
 		} else if (m_Operator == "<") {
diff --git a/lib/livestatus/livestatuslistener.cpp b/lib/livestatus/livestatuslistener.cpp
index 190b4dc6b..a942e08fd 100644
--- a/lib/livestatus/livestatuslistener.cpp
+++ b/lib/livestatus/livestatuslistener.cpp
@@ -74,13 +74,15 @@ void LivestatusListener::Start(void)
 		try {
 			socket->Bind(GetBindHost(), GetBindPort(), AF_UNSPEC);
 		} catch (std::exception&) {
-			Log(LogCritical, "LivestatusListener", "Cannot bind tcp socket on host '" + GetBindHost() + "' port '" + GetBindPort() + "'.");
+			Log(LogCritical, "LivestatusListener")
+			    << "Cannot bind TCP socket on host '" << GetBindHost() << "' port '" << GetBindPort() << "'.";
 			return;
 		}
 
 		boost::thread thread(boost::bind(&LivestatusListener::ServerThreadProc, this, socket));
 		thread.detach();
-		Log(LogInformation, "LivestatusListener", "Created tcp socket listening on host '" + GetBindHost() + "' port '" + GetBindPort() + "'.");
+		Log(LogInformation, "LivestatusListener")
+		    << "Created TCP socket listening on host '" << GetBindHost() << "' port '" << GetBindPort() << "'.";
 	}
 	else if (GetSocketType() == "unix") {
 #ifndef _WIN32
@@ -88,7 +90,8 @@ void LivestatusListener::Start(void)
 		try {
 			socket->Bind(GetSocketPath());
 		} catch (std::exception&) {
-			Log(LogCritical, "LivestatusListener", "Cannot bind unix socket in '" + GetSocketPath() + "'.");
+			Log(LogCritical, "LivestatusListener")
+			    << "Cannot bind UNIX socket to '" << GetSocketPath() << "'.";
 			return;
 		}
 
@@ -96,17 +99,17 @@ void LivestatusListener::Start(void)
 		mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 
 		if (chmod(GetSocketPath().CStr(), mode) < 0) {
-			std::ostringstream msgbuf;
-			msgbuf << "chmod() on unix socket '" << GetSocketPath() << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
-			Log(LogCritical, "LivestatusListener",  msgbuf.str());
+			Log(LogCritical, "LivestatusListener")
+			    << "chmod() on unix socket '" << GetSocketPath() << "' failed with error code " << errno << ", \"" << Utility::FormatErrorNumber(errno) << "\"";
 			return;
 		}
 
 		boost::thread thread(boost::bind(&LivestatusListener::ServerThreadProc, this, socket));
 		thread.detach();
-		Log(LogInformation, "LivestatusListener", "Created unix socket in '" + GetSocketPath() + "'.");
+		Log(LogInformation, "LivestatusListener")
+		    << "Created UNIX socket in '" << GetSocketPath() << "'.";
 #else
-		/* no unix sockets on windows */
+		/* no UNIX sockets on windows */
 		Log(LogCritical, "LivestatusListener", "Unix sockets are not supported on Windows.");
 		return;
 #endif
diff --git a/lib/livestatus/livestatusquery.cpp b/lib/livestatus/livestatusquery.cpp
index 32776d155..44a522cfd 100644
--- a/lib/livestatus/livestatusquery.cpp
+++ b/lib/livestatus/livestatusquery.cpp
@@ -206,10 +206,12 @@ LivestatusQuery::LivestatusQuery(const std::vector<String>& lines, const String&
 
 			if (header == "Or" || header == "StatsOr") {
 				filter = make_shared<OrFilter>();
-				Log(LogDebug, "LivestatusQuery", "Add OR filter for " + params + " column(s). " + Convert::ToString(deq.size()) + " filters available.");
+				Log(LogDebug, "LivestatusQuery")
+				    << "Add OR filter for " << params << " column(s). " << deq.size() << " filters available.";
 			} else {
 				filter = make_shared<AndFilter>();
-				Log(LogDebug, "LivestatusQuery", "Add AND filter for " + params + " column(s). " + Convert::ToString(deq.size()) + " filters available.");
+				Log(LogDebug, "LivestatusQuery")
+				    << "Add AND filter for " << params << " column(s). " << deq.size() << " filters available.";
 			}
 
 			if (num > deq.size()) {
@@ -221,7 +223,8 @@ LivestatusQuery::LivestatusQuery(const std::vector<String>& lines, const String&
 
 			while (num > 0 && num--) {
 				filter->AddSubFilter(deq.back());
-				Log(LogDebug, "LivestatusQuery", "Add " +  Convert::ToString(num) + " filter.");
+				Log(LogDebug, "LivestatusQuery")
+				    << "Add " << num << " filter.";
 				deq.pop_back();
 				if (&deq == &stats)
 					aggregators.pop_back();
@@ -349,7 +352,8 @@ Filter::Ptr LivestatusQuery::ParseFilter(const String& params, unsigned long& fr
 		}
 	}
 
-	Log(LogDebug, "LivestatusQuery", "Parsed filter with attr: '" + attr + "' op: '" + op + "' val: '" + val + "'.");
+	Log(LogDebug, "LivestatusQuery")
+	    << "Parsed filter with attr: '" << attr << "' op: '" << op << "' val: '" << val << "'.";
 
 	return filter;
 }
@@ -433,7 +437,8 @@ String LivestatusQuery::QuoteStringPython(const String& str) {
 
 void LivestatusQuery::ExecuteGetHelper(const Stream::Ptr& stream)
 {
-	Log(LogInformation, "LivestatusQuery", "Table: " + m_Table);
+	Log(LogInformation, "LivestatusQuery")
+	    << "Table: " << m_Table;
 
 	Table::Ptr table = Table::GetByName(m_Table, m_CompatLogPath, m_LogTimeFrom, m_LogTimeUntil);
 
@@ -538,14 +543,16 @@ void LivestatusQuery::ExecuteCommandHelper(const Stream::Ptr& stream)
 		l_ExternalCommands++;
 	}
 
-	Log(LogInformation, "LivestatusQuery", "Executing command: " + m_Command);
+	Log(LogInformation, "LivestatusQuery")
+	    << "Executing command: " << m_Command;
 	ExternalCommandProcessor::Execute(m_Command);
 	SendResponse(stream, LivestatusErrorOK, "");
 }
 
 void LivestatusQuery::ExecuteErrorHelper(const Stream::Ptr& stream)
 {
-	Log(LogDebug, "LivestatusQuery", "ERROR: Code: '" + Convert::ToString(m_ErrorCode) + "' Message: '" + m_ErrorMessage + "'.");
+	Log(LogDebug, "LivestatusQuery")
+	    << "ERROR: Code: '" << m_ErrorCode << "' Message: '" << m_ErrorMessage << "'.";
 	SendResponse(stream, m_ErrorCode, m_ErrorMessage);
 }
 
@@ -558,7 +565,7 @@ void LivestatusQuery::SendResponse(const Stream::Ptr& stream, int code, const St
 		try {
 			stream->Write(data.CStr(), data.GetLength());
 		} catch (const std::exception&) {
-			Log(LogCritical, "LivestatusQuery", "Cannot write to tcp socket.");
+			Log(LogCritical, "LivestatusQuery", "Cannot write to TCP socket.");
 		}
 	}
 }
@@ -575,14 +582,15 @@ void LivestatusQuery::PrintFixed16(const Stream::Ptr& stream, int code, const St
 	try {
 		stream->Write(header.CStr(), header.GetLength());
 	} catch (const std::exception&) {
-		Log(LogCritical, "LivestatusQuery", "Cannot write to tcp socket.");
+		Log(LogCritical, "LivestatusQuery", "Cannot write to TCP socket.");
 	}
 }
 
 bool LivestatusQuery::Execute(const Stream::Ptr& stream)
 {
 	try {
-		Log(LogInformation, "LivestatusQuery", "Executing livestatus query: " + m_Verb);
+		Log(LogInformation, "LivestatusQuery")
+		    << "Executing livestatus query: " << m_Verb;
 
 		if (m_Verb == "GET")
 			ExecuteGetHelper(stream);
diff --git a/lib/livestatus/statehisttable.cpp b/lib/livestatus/statehisttable.cpp
index 46ca67750..df2843bfa 100644
--- a/lib/livestatus/statehisttable.cpp
+++ b/lib/livestatus/statehisttable.cpp
@@ -117,7 +117,8 @@ void StateHistTable::UpdateLogEntries(const Dictionary::Ptr& log_entry_attrs, in
 
 		state_hist_service_states->Add(state_hist_bag);
 
-		Log(LogDebug, "StateHistTable", "statehist: Adding new object '" + checkable->GetName() + "' to services cache.");
+		Log(LogDebug, "StateHistTable")
+		    << "statehist: Adding new object '" << checkable->GetName() << "' to services cache.";
 	} else {
 		state_hist_service_states = m_CheckablesCache[checkable];
 		state_hist_bag = state_hist_service_states->Get(state_hist_service_states->GetLength()-1); /* fetch latest state from history */
@@ -173,8 +174,8 @@ void StateHistTable::UpdateLogEntries(const Dictionary::Ptr& log_entry_attrs, in
 
 					state_hist_service_states->Add(state_hist_bag_new);
 
-					Log(LogDebug, "StateHistTable", "statehist: State change detected for object '" +
-					    checkable->GetName() + "' in '" + log_line + "'.");
+					Log(LogDebug, "StateHistTable")
+					    << "statehist: State change detected for object '" << checkable->GetName() << "' in '" << log_line << "'.";
 				}
 				break;
 			case LogEntryTypeHostFlapping:
@@ -257,7 +258,8 @@ String StateHistTable::GetPrefix(void) const
 
 void StateHistTable::FetchRows(const AddRowFunction& addRowFn)
 {
-	Log(LogDebug, "StateHistTable", "Pre-selecting log file from " + Convert::ToString(m_TimeFrom) + " until " + Convert::ToString(m_TimeUntil));
+	Log(LogDebug, "StateHistTable")
+	    << "Pre-selecting log file from " << m_TimeFrom << " until " << m_TimeUntil;
 
 	/* create log file index */
 	LivestatusLogUtility::CreateLogIndex(m_CompatLogPath, m_LogFileIndex);
diff --git a/lib/methods/pluginchecktask.cpp b/lib/methods/pluginchecktask.cpp
index c4c260acb..dd7d6f526 100644
--- a/lib/methods/pluginchecktask.cpp
+++ b/lib/methods/pluginchecktask.cpp
@@ -58,9 +58,10 @@ void PluginCheckTask::ProcessFinishedHandler(const Checkable::Ptr& checkable, co
 {
 	if (pr.ExitStatus > 3) {
 		Process::Arguments parguments = Process::PrepareCommand(commandLine);
-		Log(LogWarning, "PluginCheckTask", "Check command for object '" + checkable->GetName() + "' (PID: " + Convert::ToString(pr.PID) +
-		    ", arguments: " + Process::PrettyPrintArguments(parguments) + ") terminated with exit code " +
-		    Convert::ToString(pr.ExitStatus) + ", output: " + pr.Output);
+		Log(LogWarning, "PluginCheckTask")
+		    << "Check command for object '" << checkable->GetName() << "' (PID: " << pr.PID
+		    << ", arguments: " << Process::PrettyPrintArguments(parguments) << ") terminated with exit code "
+		    << pr.ExitStatus << ", output: " << pr.Output;
 	}
 
 	String output = pr.Output;
diff --git a/lib/methods/plugineventtask.cpp b/lib/methods/plugineventtask.cpp
index 345a81d48..5686edd93 100644
--- a/lib/methods/plugineventtask.cpp
+++ b/lib/methods/plugineventtask.cpp
@@ -56,8 +56,9 @@ void PluginEventTask::ProcessFinishedHandler(const Checkable::Ptr& checkable, co
 {
 	if (pr.ExitStatus != 0) {
 		Process::Arguments parguments = Process::PrepareCommand(commandLine);
-		Log(LogNotice, "PluginEventTask", "Event command for object '" + checkable->GetName() + "' (PID: " + Convert::ToString(pr.PID) +
-		    ", arguments: " + Process::PrettyPrintArguments(parguments) + ") terminated with exit code " +
-		    Convert::ToString(pr.ExitStatus) + ", output: " + pr.Output);
+		Log(LogNotice, "PluginEventTask")
+		    << "Event command for object '" << checkable->GetName() << "' (PID: " << pr.PID
+		    << ", arguments: " << Process::PrettyPrintArguments(parguments) << ") terminated with exit code "
+		    << pr.ExitStatus << ", output: " << pr.Output;
 	}
 }
diff --git a/lib/methods/pluginnotificationtask.cpp b/lib/methods/pluginnotificationtask.cpp
index 362c279de..a10c0beab 100644
--- a/lib/methods/pluginnotificationtask.cpp
+++ b/lib/methods/pluginnotificationtask.cpp
@@ -70,8 +70,9 @@ void PluginNotificationTask::ProcessFinishedHandler(const Checkable::Ptr& checka
 {
 	if (pr.ExitStatus != 0) {
 		Process::Arguments parguments = Process::PrepareCommand(commandLine);
-		Log(LogWarning, "PluginNotificationTask", "Notification command for object '" + checkable->GetName() + "' (PID: " + Convert::ToString(pr.PID) +
-		    ", arguments: " + Process::PrettyPrintArguments(parguments) + ") terminated with exit code " +
-		    Convert::ToString(pr.ExitStatus) + ", output: " + pr.Output);
+		Log(LogWarning, "PluginNotificationTask")
+		    << "Notification command for object '" << checkable->GetName() << "' (PID: " << pr.PID
+		    << ", arguments: " << Process::PrettyPrintArguments(parguments) << ") terminated with exit code "
+		    << pr.ExitStatus << ", output: " << pr.Output;
 	}
 }
diff --git a/lib/notification/notificationcomponent.cpp b/lib/notification/notificationcomponent.cpp
index c2da95cf9..522e7a6e1 100644
--- a/lib/notification/notificationcomponent.cpp
+++ b/lib/notification/notificationcomponent.cpp
@@ -112,15 +112,13 @@ void NotificationComponent::NotificationTimerHandler(void)
 		}
 
 		try {
-			Log(LogInformation, "NotificationComponent", "Sending reminder notification for object '" + checkable->GetName() + "'");
+			Log(LogInformation, "NotificationComponent")
+			    << "Sending reminder notification for object '" << checkable->GetName() << "'";
 			notification->BeginExecuteNotification(NotificationProblem, checkable->GetLastCheckResult(), false);
 		} catch (const std::exception& ex) {
-			std::ostringstream msgbuf;
-			msgbuf << "Exception occured during notification for object '"
-			       << GetName() << "': " << DiagnosticInformation(ex);
-			String message = msgbuf.str();
-
-			Log(LogWarning, "NotificationComponent", message);
+			Log(LogWarning, "NotificationComponent")
+			    << "Exception occured during notification for object '"
+			    << GetName() << "': " << DiagnosticInformation(ex);
 		}
 	}
 }
diff --git a/lib/perfdata/graphitewriter.cpp b/lib/perfdata/graphitewriter.cpp
index 18397905b..ac1ef3714 100644
--- a/lib/perfdata/graphitewriter.cpp
+++ b/lib/perfdata/graphitewriter.cpp
@@ -177,7 +177,8 @@ void GraphiteWriter::SendMetric(const String& prefix, const String& name, double
 	std::ostringstream msgbuf;
 	msgbuf << prefix << "." << name << " " << Convert::ToString(value) << " " << static_cast<long>(Utility::GetTime());
 
-	Log(LogDebug, "GraphiteWriter", "Add to metric list:'" + msgbuf.str() + "'.");
+	Log(LogDebug, "GraphiteWriter")
+	    << "Add to metric list:'" << msgbuf.str() << "'.";
 
 	// do not send \n to debug log
 	msgbuf << "\n";
@@ -191,7 +192,8 @@ void GraphiteWriter::SendMetric(const String& prefix, const String& name, double
 	try {
 		m_Stream->Write(metric.CStr(), metric.GetLength());
 	} catch (const std::exception& ex) {
-		Log(LogCritical, "GraphiteWriter", "Cannot write to TCP socket on host '" + GetHost() + "' port '" + GetPort() + "'.");
+		Log(LogCritical, "GraphiteWriter")
+		    << "Cannot write to TCP socket on host '" << GetHost() << "' port '" << GetPort() << "'.";
 
 		m_Stream.reset();
 	}
diff --git a/lib/perfdata/perfdatawriter.cpp b/lib/perfdata/perfdatawriter.cpp
index 445f34fc2..05b4e059f 100644
--- a/lib/perfdata/perfdatawriter.cpp
+++ b/lib/perfdata/perfdatawriter.cpp
@@ -122,7 +122,8 @@ void PerfdataWriter::RotateFile(std::ofstream& output, const String& temp_path,
 	output.open(temp_path.CStr());
 
 	if (!output.good())
-		Log(LogWarning, "PerfdataWriter", "Could not open perfdata file '" + temp_path + "' for writing. Perfdata will be lost.");
+		Log(LogWarning, "PerfdataWriter")
+		    << "Could not open perfdata file '" << temp_path << "' for writing. Perfdata will be lost.";
 }
 
 void PerfdataWriter::RotationTimerHandler(void)
diff --git a/lib/remote/apiclient.cpp b/lib/remote/apiclient.cpp
index 966a62f73..644bd1152 100644
--- a/lib/remote/apiclient.cpp
+++ b/lib/remote/apiclient.cpp
@@ -75,7 +75,8 @@ ConnectionRole ApiClient::GetRole(void) const
 void ApiClient::SendMessage(const Dictionary::Ptr& message)
 {
 	if (m_WriteQueue.GetLength() > 20000) {
-		Log(LogWarning, "remote", "Closing connection for API identity '" + m_Identity + "': Too many queued messages.");
+		Log(LogWarning, "remote")
+		    << "Closing connection for API identity '" << m_Identity << "': Too many queued messages.";
 		Disconnect();
 		return;
 	}
@@ -93,11 +94,12 @@ void ApiClient::SendMessageSync(const Dictionary::Ptr& message)
 		if (message->Get("method") != "log::SetLogPosition")
 			m_Seen = Utility::GetTime();
 	} catch (const std::exception& ex) {
-		std::ostringstream info, debug;
+		std::ostringstream info;
 		info << "Error while sending JSON-RPC message for identity '" << m_Identity << "'";
-		debug << info.str() << std::endl << DiagnosticInformation(ex);
-		Log(LogWarning, "ApiClient", info.str());
-		Log(LogDebug, "ApiClient", debug.str());
+		Log(LogWarning, "ApiClient")
+		    << info.str();
+		Log(LogDebug, "ApiClient")
+		    << info.str() << "\n" << DiagnosticInformation(ex);
 
 		Disconnect();
 	}
@@ -110,7 +112,8 @@ void ApiClient::Disconnect(void)
 
 void ApiClient::DisconnectSync(void)
 {
-	Log(LogWarning, "ApiClient", "API client disconnected for identity '" + m_Identity + "'");
+	Log(LogWarning, "ApiClient")
+	    << "API client disconnected for identity '" << m_Identity << "'";
 
 	if (m_Endpoint)
 		m_Endpoint->RemoveClient(GetSelf());
@@ -168,7 +171,8 @@ bool ApiClient::ProcessMessage(void)
 
 	String method = message->Get("method");
 
-	Log(LogNotice, "ApiClient", "Received '" + method + "' message from '" + m_Identity + "'");
+	Log(LogNotice, "ApiClient")
+	    << "Received '" << method << "' message from '" << m_Identity << "'";
 
 	Dictionary::Ptr resultMessage = make_shared<Dictionary>();
 
diff --git a/lib/remote/apilistener.cpp b/lib/remote/apilistener.cpp
index ca9b5bdcc..9ec2f5e76 100644
--- a/lib/remote/apilistener.cpp
+++ b/lib/remote/apilistener.cpp
@@ -293,13 +293,8 @@ void ApiListener::NewClientHandler(const Socket::Ptr& client, ConnectionRole rol
 
 	bool verify_ok = tlsStream->IsVerifyOK();
 
-	std::ostringstream msgbuf;
-	msgbuf << "New client connection for identity '" << identity << "'";
-
-	if (!verify_ok)
-		msgbuf << " (unauthenticated)";
-
-	Log(LogInformation, "ApiListener", msgbuf.str());
+	Log(LogInformation, "ApiListener")
+	    << "New client connection for identity '" << identity << "'" << (verify_ok ? "" : " (unauthenticated");
 
 	Endpoint::Ptr endpoint;