Looking at [the Logback demo page][1] the following works for the 'CyclicBufferAppender':

    <appender name="CYCLIC" class="ch.qos.logback.core.read.CyclicBufferAppender">
      <MaxSize>512</MaxSize>
    </appender>

I have not tried it, but this may also be the same syntax for the RollingFileAppender.


  [1]: http://logback.qos.ch/demo.html