$CATALINA_HOME/conf/logback.xml

<configuration debug="true" scan="true">
  <appender name="RFILE" class="org.apache.juli.logging.ch.qos.logback.core.rolling.RollingFileAppender">
    <!--See also http://logback.qos.ch/manual/appenders.html#RollingFileAppender-->
    <File>${catalina.base}/logs/tomcat.log</File>
    <encoder>
      <pattern>%d{HH:mm:ss.SSS} %-5level %logger{40} - %msg%n</pattern>
    </encoder>
    <rollingPolicy class="org.apache.juli.logging.ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <!-- Rollover file daily. -->
      <fileNamePattern>${catalina.base}/logs/tomcat.%d.log</fileNamePattern>
      <!-- Keep 30 days of history. -->
      <maxHistory>30</maxHistory>
    </rollingPolicy>
  </appender>
  <root level="INFO">
    <appender-ref ref="RFILE"/>
  </root>
</configuration>