J2EE correct JVM heap parameters for AIX 5.3

[Former Member]

I would like to tune the J2EE engine. I keep getting GC that stops the services. Does anyone have AIX 5.3 JVM parameters that have proved to minimize garbage collecting. I have read through the AIX JVM SAP notes.

After reading through the note it states the set max heap however it is not clear whether to apply to server dispatcher and bootstrap.

Thanks

John

[former_member197561 · Accepted solution]

Dear John,

In the past AIX OS JVM settings were those:

https://css.wdf.sap.corp/sap/bc/bsp/spn/sapnotes/index2.htm?numm=0001008311

Currently SAP JVM is also supported on AIX. By default, via the so called "zero-admin configuration templates", the SAP Java Server comes with optimized settings for garbage collection algoriths. The heap is automatically defined by the available system memory and the number of configured server nodes.

Best regards,

Sylvia

[martin_moser]

Hi Ryan,

There should be an optimized set of VM parameters and a configuration recommendation available from IBM. Please contact stephan.gregg@de.ibm.com on this, and refer to me.

Regards,

Martin

[Former Member]

John,

I suppose you have 64bit, so you can go quite high with the memory. If you have issues with long GC stopping services then you would do better to use more server processes and smaller heaps - which yields shorted GCs. If you have problem with too frequent GCs then you should increase your heap.

As for the dispatcher and bootstrap, those don't require any tuning beyond the defaults set during installation. You need to concentrate on the server nodes.

You should run with verbosegc and post the collections to give us a chance to comment.

Nick