1. log setting:<appender name="DebugAppender"
        class="ch.qos.logback.core.rolling.RollingFileAppender">

  <file>${loggerHome}/logs/${moduleName}/debug/${moduleName}_debug.log</file>
  <append>true</append>

  <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
   
   <fileNamePattern>${loggerHome}/logs/${moduleName}/debug/${moduleName}debug%d{yyyyMMddHH{color}}_%i.log</fileNamePattern>
   <maxHistory>2</maxHistory>
   <CleanHistoryOnStart>true</CleanHistoryOnStart>

   <maxFileSize>100MB</maxFileSize>
  </rollingPolicy>

  <encoder charset="UTF-8">
   <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS}|%-5level|[%thread]|%m%n%</pattern>
  </encoder>

 </appender>

1. after set the CleanhistoryOnStart to true,  the history log cann't be deleted base on the rule.
2. debugging the code,find the issue :ch.qos.logback.core.rolling.helper.RollingCalendar public long periodBarriersCrossed(long start, long end) {
           if (start > end)
               throw new IllegalArgumentException("Start cannot come before end");

        long startFloored = getStartOfCurrentPeriodWithGMTOffsetCorrection(start, getTimeZone());
        long endFloored = getStartOfCurrentPeriodWithGMTOffsetCorrection(end, getTimeZone());

        long diff = endFloored - startFloored;

        switch (periodicityType) {

        case TOP_OF_MILLISECOND:
            return diff;
        case TOP_OF_SECOND:
            return diff / MILLIS_IN_ONE_SECOND;
        case TOP_OF_MINUTE:
            return diff / MILLIS_IN_ONE_MINUTE;
        case TOP_OF_HOUR:

            return (int) diff / MILLIS_IN_ONE_HOUR;
        case TOP_OF_DAY:
            return diff / MILLIS_IN_ONE_DAY;
        case TOP_OF_WEEK:
            return diff / MILLIS_IN_ONE_WEEK;
        case TOP_OF_MONTH:
            return diffInMonths(start, end);
        default:
            throw new IllegalStateException("Unknown periodicity type.");
        }
    }

the red color code will return the number below 0. because covert long to int . the value will be < 0.

It's the reason why we cann't delete the history logs after system start