The Dreaded PermGen Error

[Flannery, Sean]

I do not run the IDP and am not an expert on that, but perhaps I can help
you with the java part of your question


1. Increasing your MaxPermGenSize will, yes, only delay the invietable
crash * if you have a class loader leak * but if you don't have a leak it
could very well fix your problem.  Are you sure you have a leak?  I doubt
Shibboleth has a native leak.  Have you tried a higher value?  Personally,
I would increase your -XX:MaxPermSize option and see if it fixes the issue.


2. If increasing your PermGenSize does not help and you really have a
class loader leaak- they are tricky to fix and the only real solution is
to find it in a dev environment and fix it, i.e. there isn't a good way
(that I know of) to be proactive about it.

This website details how to trouble shoot such problems if you feel you do
have a class loader leak:

http://frankkieviet.blogspot.ca/2006/10/classloader-leaks-dreaded-permgen-s
pace.html




From:  Joshua Riffle <jriffle at apu.edu>
Reply-To:  Shib Users <users at shibboleth.net>
Date:  Monday, November 11, 2013 10:23 AM
To:  users <users at shibboleth.net>
Subject:  The Dreaded PermGen Error


We have been getting this error from time to time with our Shibboleth
Identity Provider in Tomcat 6 and before you reply to this thread...


1) Yes I know this is caused by a memory leak and can be 'mitigated' by
increasing the max permgen size:

https://wiki.shibboleth.net/confluence/display/SHIB2/IdPApacheTomcatPrepare
 <https://wiki.shibboleth.net/confluence/display/SHIB2/IdPApacheTomcatPrepa
re>


2) Or better yet possibly resolved in Tomcat 7:
http://wiki.apache.org/tomcat/MemoryLeakProtection
<http://wiki.apache.org/tomcat/MemoryLeakProtection>


-- What I don't know and would LOVE input on is:


1) How do you detect or prevent the evil PermGen error beforehand? My
understanding is increasing the MaxPermGenSize is only delaying the
inevitable memory leak build up.


2) Better yet: Best practices? What have you already done in your
architecture to avoid or defeat this kind of issue?

Joshua RiffleSoftware Engineer
Azusa Pacific University