[opencms-dev] JVM Tuning reccomendations for OpenCMS

[Brendon Price]

Hi Paul,

Our box is not a dual processor machine, so this may have nothing to do with
the issue.

I have had a fair bit of experience with tunning JVM's using SUN JDK 1.3.1
used with BEA weblogic, but the GC has changed a bit under JDK 1.4, so I
feel a little out of my depth.

Most of our experience is related to the SUN JDK running out of Memory, and
failing to do pre-emptive garbage collection. However I have not seen any
evidence of this with OpenCMS.

A popular band aid mentioned for the "out of memory" issue is using
-XX:MaxPermSize=128Mb
However this may have nothing to do with your issue, I just through it out
as an option :-)

I will post any further findings as and when I find some more info.

Regards
Brendon

-----Original Message-----
From: Paul Adams [mailto:paul.adams at satsumas.com]
Sent: Wednesday, 4 June 2003 5:38 p.m.
To: Brendon Price; opencms-dev at opencms.org
Subject: RE: [opencms-dev] JVM Tuning reccomendations for OpenCMS


Hi Brendon,
 
Interesting -- Our configuration is very similar:
 
RedHat 8.0
Apache 2 with jk2 connector
Tomcat 4.1.18
Sun JDK 1.4.1

We originally ran with no JAVA_OPTS, taking the default JVM settings. The
performance was terrible. I added the memory options I documented in my last
post and the performance was better, but we get the gradual degradation
noted.
 
I also think our server is dual processor and I believe we're using the dp
kernel. Could this be an issue?
 
I have been reading this document from Sun
 
http://java.sun.com/docs/hotspot/gc1.4.2/
 
and was wondering if upping the ammount of memory reserved for "young"
objects might improve things (Just a hunch based on editing must be creating
and destroying loads of objects). Unfortunately our Linux operator is away
and I cannot make changes until Friday. You could try upping the "NewSize"
options and see if this helps, but it may only be a bandaid solution.
 
Any other suggestions gladly accepted :-)
 
Regards
Paul.
 

	-----Original Message----- 
	From: Brendon Price [mailto:Brendon.Price at sytec.co.nz] 
	Sent: Wed 4/06/2003 15:16 
	To: 'opencms-dev at opencms.org' 
	Cc: Paul Adams 
	Subject: RE: [opencms-dev] JVM Tuning reccomendations for OpenCMS
	
	

	Hi Paul,
	
	We have noticed a similar problem, running OpenCMS 5.0.0
	
	RedHat 8.0
	Apache 2 with mod_jk connector
	Tomcat 4.1
	IBM JDK 1.4.0
	
	Are you using the SUN JDK, IBM or another?
	
	At this point in time we are unsure of where the real issue lies, so
I can't
	provide
	any tuning tips at this point in time.
	
	Regards
	Brendon
	
	-----Original Message-----
	From: Paul Adams [mailto:paul.adams at satsumas.com]
	Sent: Wednesday, 4 June 2003 4:59 p.m.
	To: opencms-dev at opencms.org
	Subject: [opencms-dev] JVM Tuning reccomendations for OpenCMS
	
	
	Hi,
	
	We have been noticing a gradual performance degradation in the
OpenCMS 5.0
	RC2 workplace running under Tomcat on Redhat Linux 8. With two users
editing
	documents over a period of 2-3 hours, the workplace slows down to
the point
	where a complete refresh will take up to 60 seconds.
	
	The Server has 512Mb of RAM and 1Gb of swap space.
	
	Our current JVM runtime parameters are:
	
	-Server -Xincgc -Xms256m -Xmx256m -XX:NewSize=128m
-XX:MaxNewSize=128m
	
	Has anyone got any tuning tips for use with OpenCMS?
	
	Regards
	Paul Adams.
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