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WiWildcat
Inspiring
May 5, 2014
Answered

Java Heap Size Recommendation Request

  • May 5, 2014
  • 1 reply
  • 630 views

Looking for suggestions on tuning. Running CF10 update 13 on a 64 bit server with 8 GB RAM, running into memory issues (I suspect). JVM is only set to 256 / 512 right now, so I'm going to increase it. CF and a handful of sites is pretty much all this server does.

Suggestions on what I should set this to now? We seem to be under 50% memory usage at the present time (right now 3.44GB), and CPU is 0-2%.

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Correct answer carl type3

Hi,

Perhaps set JVM minimum and maximum to 2048 / 4096. While your altering JVM apply a minimum setting for Permanent Generation and set maximum for permanent larger EG:
-XX:PermSize=284m -XX:MaxPermSize=512m

You could do well to perform some CF Java monitoring to know what values suit best and if indeed the garbage collections run by -XX:+UseParallelGC are working optimally. Java logging can be run by doing some traditional Java logging to a file then read file or pass file thru a tool. You can also use Jconsole, Jvisualvm or even the new Mission Control (in 1.7.0_40 release onwards) graphical tools.

HTH, Carl.

1 reply

C
carl type3Correct answer
Legend
May 5, 2014

Hi,

Perhaps set JVM minimum and maximum to 2048 / 4096. While your altering JVM apply a minimum setting for Permanent Generation and set maximum for permanent larger EG:
-XX:PermSize=284m -XX:MaxPermSize=512m

You could do well to perform some CF Java monitoring to know what values suit best and if indeed the garbage collections run by -XX:+UseParallelGC are working optimally. Java logging can be run by doing some traditional Java logging to a file then read file or pass file thru a tool. You can also use Jconsole, Jvisualvm or even the new Mission Control (in 1.7.0_40 release onwards) graphical tools.

HTH, Carl.

W
WiWildcatAuthor
Inspiring
May 6, 2014

Carl,

Thank you! I appreciate your answer very much, with reasoning and a holistic view.

I will look into Java monitoring. Have not done that yet, but always looking to upgrade my skills.

I can set JVM in CF Admin and have done so. I know there are some things you can do to activate the jvm config file but I haven't had the need to mess with that yet. Thought I changed it once, but it was reset when I restarted CF so swing and a miss.

Systems running better already though with that huge headroom in memory.

Thanks again!

RLS

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