As sais here, using FileAppender or any "common" subclass leads to errors on clusters http://www.oreillynet.com/cs/user/view/cs_msg/17235. The problem is due to Log4J not rolling the files consulting the underlying system. Log4J mantains a counter of how many bytes has written to the file. So every node has it's own counter and when another node has already rolled the file, you find that problem. | protected | void subAppend(LoggingEvent event) { | super.subAppend(event); | if((fileName != null) && | ((CountingQuietWriter) qw).getCount() >= maxFileSize) | this.rollOver(); | } | As said in the post of the url I've given you sould either subclass RollingFileAppender and change it's subAppend method or use any other mean of logging, like JMS or JMX. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4084643#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...