In an old blog post entitled "Verbose GC output. Performance Problem or Always On Monitoring?" we covered how to log verbose:gc output to a single file or series of circular log files. This helps to maintain a history of GC activity which is a good thing for analysing a number of memory and performance related issues.
A number of applications have in-built High Availability features, which usually work by causing the application to be automatically restarted if an outage is detected. This minimizes downtime, but can result in a number of log files from the previous application instance being over-written by the new process.
This can be avoided in the case of the verbose:gc log file, and a number of other log files produced by the IBM Java Runtimes, using a %pid substitution in the file name, eg.
-Xverbosegclog:/logs/vgc.%pid.outwill cause the process id to be included in the file name.