Confluence and Jra OutOfMemory errors

Last year we installed Confluence into Jira Standalone. Everything was perfect during trial period on QA server, but as soon as real user started to use JIRA and Confluence both applications started to fail with this error: java.lang.OutOfMemoryError: PermGen space. The issue was fixed by setting the -XX:MaxPermSize=128m memory property in JAVA_OPTS as it properly described in 'Add Confluence EAR-WAR to JIRA Standalone' manual on Atlassian site:

Step 4 - Modify your setenv.sh/bat (ONLY IF YOU ARE RUNNING A SUN MICROSYSTEMS JVM)

1. Open JIRA's bin/setenv.sh/bat (.sh on unix, .bat on windows) in a text editor.
2. Find the line that says: "... JAVA_OPTS=... " and add -XX:MaxPermSize=128m to its end.

The Java Virtual Machine sets aside a portion of memory as the "permanent space", for objects that it never expects to have to garbage-collect. Because JIRA and Confluence are both quite large applications, it is possible that this permanent space will be filled up. Increasing the application heap size will not help, because the permanent generation size is a separate setting.

Anyway I need to consider switching to running Confluence Standalone separately during next Confluence or Jira upgrade.