Liferay's primary log configuration is managed in the portal-log4j.xml file (which is packed inside the portal application's WEB-INF/lib/portal-impl.jar).
As with many other configuration files, Liferay provides administrators with a second configuration file, portal-log4j-ext.xml (located in the portal application's /WEB-INF/classes/META-INF/ directory), which can be used to override settings in the main portal-log4j.xml file.
Both of these files are in standard log4j XML configuration format. Both files allow creating and modifying appenders, binding appenders to loggers, and adjusting the default log verbosity of different classes and packages. By default, the Endeca override file portal-log4j-ext.xml specifics a log verbosity of INFO for the com.endeca and com.endeca.portal.instrumentation packages. Endeca does not override any of the default log verbosity settings specified for non-Endeca components packaged in portal-log4j.xml.