Maximum backup index for RollingFileAppender

[Peter Steele]

We use a RollingFileAppender defined as follows:

 

   <appender name="FILE" class="org.apache.log4j.RollingFileAppender">

       <param name="maxFileSize" value="200MB" />

       <param name="maxBackupIndex" value="20" />

       <param name="File" value="${LOGNAME}" />

       <param name="Append" value="false"/>

       <layout class="org.apache.log4j.PatternLayout">

           <param name="ConversionPattern" 

               value="%d{MM-dd HH:mm:ss.SSS} %5p %c{1} - %m%n" />

       </layout>

   </appender>

 

It works fine, except that the maxBackupIndex appears to top out at 13,
even though we have 20 specified. Are we doing something wrong or is 13
a hard coded maximum for this field?