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From Kevan Miller <kevan.mil...@gmail.com>
Subject Re: Geronimo Perm Size
Date Wed, 19 Aug 2009 16:34:09 GMT

On Aug 18, 2009, at 2:24 PM, Russell Collins wrote:

> I am having an issue with Geronimo and memory.  First, this could be  
> a configuration issue or a memory leak.  Here is what happens.
>
> ·         When we build java objects, we deploy to the Geronimo  
> application server.
> ·         We then run Junit tests to test the remote interface and  
> bring back data objects
> ·         Most of the time, this works without a hitch.  However,  
> after a while (say a good week or so) everything will break and say  
> that we are out of memory (perm size)
>
> I know that one on the actions that can be taken is to update the  
> perm size.  First question is to how to do this correctly for  
> Geronimo?  Second, what is the ideal perm size (if there is one) for  
> Geronimo.

What version of Geronimo?

I assume by "deploy" you mean deploy/undeploy?

Typically, there are two causes of PermGen OOME's:

1) Your application(s) are too large, and you need to increase your - 
XX:MaxPermSize= setting
2) If you are deploying/undeploying applications, and your PermGen  
utilization keeps increasing, then you have a ClassLoader memory leak.  
Bumping your MaxPermSize setting will postpone your OOME, but it's  
only a matter of time.

2) is a bug -- either in Geronimo, your application, or libraries  
included with your application.

The best way I've found to diagnose is to set "-XX:- 
HeapDumpOnOutOfMemoryError". This will cause the JVM to generate a  
head dump when it encounters an OutOfMemoryError. This will create a  
java_pid<pid>.hprof file in the current directory. There are some  
additional controls (e.g. you can configure a destination directory  
for the hprof file, but I just let it go to the working directory...).

Using the .hprof file, it's then possible to perform post-mortem  
analysis. Best tools that I've found for this are either YourKit or  
Eclipse Memory Analyzer (MAT).

If you have a test case that you can share, I'll take a look at it. Or  
if you generate a heap dump, I can help look at that...

--kevan
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