I never used log4j2 so far but the documentation of the RollingFileAppender gives you a lot of configuration examples.
Interesting for you seams to be something like this (using DefaultRolloverStrategy
):
<RollingFile name="RollingFile" fileName="logs/app.log"
filePattern="logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
<PatternLayout>
<pattern>%d %p %C{1.} [%t] %m%n</pattern>
</PatternLayout>
<Policies>
<SizeBasedTriggeringPolicy size="5 MB"/>
</Policies>
<DefaultRolloverStrategy max="20"/>
</RollingFile>