JVM recommended memory settings?

[janny_buh]

I'm building a clustered environment for OXSE (6.14 as soon as available) using two Dell PowerEdge 1950 with 6GB RAM.

I'm following this guide:
Load balancing and clustering Open-Xchange

but I don't see any hint regarding JVM memory configuration.

Looking at this file:
/opt/open-xchange/etc/groupware/ox-scriptconf.sh

I see that the default JVM settings are:
JAVA_XTRAOPTS="-Xms512m -Xmx512m -XX:+UseConcMarkSweepGC -XX:NewSize=256m -XX:MaxNewSize=256m -XX:SurvivorRatio=6"

I've just installed RHEL 5 (64 bit version) on both machines and I would like to optimize JVM settings for taking advantage of the available memory (6GB physical RAM).
Any advise?

[Martin Heiland]

Hi,

this depends on what services are running on the machine. If it's purely for OX you might use 4-5GB for OX which means -Xmx4096m for example. If you're running several other services like databases on the same machine you might want to use less memory for ox to avoid out of memory situations. The "Xmx" flag defines the maximum amount of memory the JVM can allocate. Note that the JVM might also allocate this memory even if it's not really used by OX.

By the way: if you find any issues at this guide, please contact me or post it somewhere

Greetings

[janny_buh]

Thanks Martin
Each server will only run the Apache daemon.
I'll adjust the Xmx parameter to 4GB o a bit higher (Xms should also be tweaked to 4GB?), I don't know if NewSize, MaxNewSize and SurvivorRatio should be also changed...

[Martin Heiland]

Hi,

basically you can drop everything except
-Xms512m -Xmx512m -XX:+UseConcMarkSweepGC

other parameters use java defaults which are okay.

Greetings