As distributed, Bamboo's log4j.properties file directs INFO level output to both atlassian-bamboo.log and "console" which, in Tomcat, is the catalina.out file. While the "atlassian-bamboo.log" file is configured to be a RollingFileAppender, the "catalina.out" file is not, and it grows very quickly. Since detailed information is being logged to "atlassian-bamboo.log", it probably doesn't also need to appear in "catalina.out". I have modified Bamboo's log4j.properties file to change this line:

log4j.rootLogger=INFO, console, filelog

to:

log4j.rootLogger=INFO, filelog

I recommend that you consider making this configuration, or something like it, the default for future distributions.