JVM Configuration

[sankal]

Hi All,

Just wanted to enter this thread to get any response/feedback about the
settings that we are thinking of putting up on production.
We have Windows machine with 4GB memory and 4 CPU dual core and CFMX7.0.1. The
database server is Linux 10g.
We are lately having high traffic and always seeing that Jrun goes too high
and stops responding.
The JVM setting that I'm planning is as below

java.args=-server -DJINTEGRA_NATIVE_MODE -DJINTEGRA_PREFETCH_ENUMS -Xms1280m
-Xmx1280m -Dsun.io.useCanonCaches=false -XX:NewSize=512m -XX:MaxNewSize=512m
-XX:PermSize=256m -XX:MaxPermSize=256m -XX:+DisableExplicitGC
-XX:+UseParallelGC -XX:ParallelGCThreads=8 -XX:+UseAdaptiveSizePolicy
-XX:MaxTenuringThreshold=0 -XX:SurvivorRatio=128
-Dcoldfusion.rootDir={application.home}/../
-Dcoldfusion.libPath={application.home}/../lib
-Dcoldfusion.classPath={application.home}/../../classes,{application.home}/../li
b/updates,{application.home}/../lib/,{application.home}/../gateway/lib/,{applica
tion.home}/../wwwroot/WEB-INF/cfform/jars


Even if I have 4GB of memory, CF is not allowing to set it higher then around
13m

Any feedback/Corrections are appreciated.

Thanks,

[BKBK]

> Even if I have 4GB of memory...
It's not all about RAM. Processor architecture can impose a ceiling on the
amount of memory available to the JVM. For example, on 32-bit processor
machines the maximum possible heapsize is usually around 1.9GB, irrespective of
RAM. It is the so-called contiguous memory address space. There is a
[url]http://www.adobe.com/cfusion/knowledgebase/index.cfm?id=tn_19359[/url].

Java's native(process) heap and garbage collector share the 1.9GB memory
address space. So, making the maximum heap size Xmx too large can impair
garbage collection. I would not go beyond an Xmx value 1024MB.

[ke4pym]

I'll second pulling -Xmx back to 1024. I'd also pull -Xms back to around
512MB. You might also want to investigate -XX:+UseConcMarkSweepGC and
-XX:+UseParNewGC - they're much more efficient GC's than ParallelGC.