J2EE: multiple server processes?

[Former Member]

Hi guys

A j2ee instance usually has a dispatcher and one server process (server0). In the past we were always running our instances with that setup. Obviously we are having lots of trouble, caused be extensive garbage collection, thread lockups, process restarts and the like.

On a BI 7.0 portal on HP IA64 things were pretty bad. Now we added a server1 process and the overall situation improved significantly.

Can you please share your opionion on multiple server processes? How many processes do you have on which usage types and on which hardware platform?

Regards, Michael

[former_member59864 · Accepted solution]

3 Server process for each dispatcher is the best solution fin my opinion take in mind Slava's suggestions

[Former Member]

Thanks so far, just to be precise, i am not particularly looking at how i should configure my j2ee. I know sap note 723909 very well i did even test the UseConcMarkSweepGC parameter:

We still do NOT recommend -XX:+UseConcMarkSweepGC (it caused VM crashes in earlier JDK 1.4.2 versions) but we're re-evauating it now based on most actual JDKs.

...with mixed results btw

I would be rather interested in your configurations and experiences. I still consider multiple j2ee servers as non-standard, as you have only one at installation time. So if you would like to share, go on.

Regards Michael

Edit: so far, i think we agree that 2 or 3 server processes with a heap of 2-2.5gb per instance are a good setup, as long as cpu and memory ressources permit it.

[Former Member]

Hi,

We put at least 2 server processes by dispatcher process.

In my opinion, this should not be necessary and is only a workaround because of the lack of reliability of the java stack...

I hope that the situation will improve with Netweaver 7.2 and the SAP JVM !

Regards,

Olivier

[former_member151028]

Hi Michael,

Please consider the SAP note 723909 (Java VM settings for J2EE 6.40/7.0) as well:

The max heap size (plus max perm size) of all Java server nodes must fit completely into the physical memory in order to avoid heavy paging on OS level. You must also consider the space needed for OS and other processes.

For each JavaVM on the server, all Java memory must fit completely into

physical memory (no paging)!

Therefore the rule of thumb for number of server nodes for SUN and HP

JavaVM with 1 GB Heap each will be

#ServerNodes = (AvailableMemory / 1.5 GB)

and factor 2.5 should be used instead of 1.5 for 64 bit with 2GB heap

size.

Also remember, if the instance contains more than three server nodes SAP recommends to add 50MB of dispatcher heap for each additional server node.

Regards,

Matheus

[Former Member]

On EP and BI 2-3 server processes per instance with 2GB heap memory each.

More than that causes Java long time to start due to high CPU utilization.

After that - scaling horizontally by adding more app servers and do load balancing.

It depends, of course, of your hardware.

JVM parameters also play a big role in the performance.

SAP has recommendations:

SAP Note Number: 723909 "Java VM settings for J2EE 6.40/7.0"

Regards,

Slava