running confluence version 5.1 on VMWare VM and Java is using 99% of memory.


I've looked through some of Atlasssian's JIRA but can't find information relating to JAVA using 99% of the available CPU. I looked through the Confluenc 5.1 logs and other than various warnings, about REST, I don't see any error messages. Reboot the VM causes the problem to disappear for 24 hours but then it roars back. How do I get more information?

Shirley Stephan

2 answers

1 accepted

There are few reasons why this could happened. It could be due to a memory leak from a plugin, poorly configured instance or lack of memory in general. I'd suggest to configure parallel collector -XX:+UseParallelOldGC in your instance, create a support ticket to us at and include Confluence Support Zip in the ticket for further check up. To configure parallel collector, you may refer here:

Thanks for the information. I will investigate your suggestions and let you know what I find. I really appreciate your thoughtful assistance.

Thanks again. I've rebooted the vm (gave it 4GB instead of 3GB memory) and now using:

-XX:+UseParallelOldGC and -XX:MaxPermSize=1024m

I will see how it runs and report back.

If there's still a problem, I will try the suggestions in Matthew Cobby's post and if it's still a problem, I'll open a support ticket with the "Confluence Support Zip" as you suggested. Again, thank you very much.

The increased permgen and garbage collection hit the spot. It's been running a week without issue. THANKS!

Great to hear that! ;)

Hi there,

Quick question... when you say "reboot the VM" is that the VMware VM or the Java VM? You don't need to restart the VM, just the JVM is enough.

Are you running an extra plugins? Does the problem occure in Safe mode?

As a general back ground read, you should look at

You could also use JMX to connect to the JVM and wait for the problem to occur. You could then get a stack trace out of the JVm and see what piece of code is running at 99%

Two JMX clients to choose are:



and how to setup your server with JMX

are you getting any errors in the logs?

What is your memory configuration for the JVM (how much memory have you given it)

Could simply be that you are running on the defaults and your instance has grown and now needs more memory.

Thanks for the information. I will try all the suggestions and let you know what I find. I really apprecaite your knowledge!

I restarted the VM itself to add more memory. I examined the log files and didn't find anything that leapt out. I increased the memory and other perameters and if that doesn't solve this runaway CPU usage, I'll work through your excellent suggestions. Thank you very much for taking the time to answer my question.

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