This is my logback settings, I set single log size 500MB, and the minIndex is 1,max is 5.
<appender name="extractorAppender"
class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>/data/logs/extractor.log</file>
<append>true</append>
<rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
<fileNamePattern>/data/logs/extractor.%i.log
</fileNamePattern>
<minIndex>1</minIndex>
<maxIndex>5</maxIndex>
</rollingPolicy>
<triggeringPolicy
class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
<maxFileSize>500MB</maxFileSize>
</triggeringPolicy>
<encoder>
<pattern>%d

%p %t - %m%n</pattern>
<charset class="java.nio.charset.Charset">UTF-8</charset>
</encoder>
</appender>
but in my production environment, I found a log file up to 82G and a 966MB log file, and my linux system's disk space was used off.