The documentation states that LogbackValve will try to find a configuration file named logback-access.xml in the directory where tomcat servet.xml is located and that this directory is $TOMCAT_HOME/conf/.

This is not correct because if you run multiple instances of tomcat (by splitting tomcat in BASE and HOME directories), the server.xml could be located in $TOMCAT_BASE/conf/ which defaults to $TOMCAT_HOME/conf/ if you do not use such settings.

Therefore, LogbackValve should try to find logback-access.xml in $TOMCAT_BASE/conf/ instead.