IBM Application Server Crash with JVMCI015:OutOfMemoryError

[prashanth]

Hi,
I was wondering if you someone can provide some guidance as to the
maximum allowable heap size for the IBM JVM when running on Windows
Server 2003. Somewhere I heard that the max is 2048 MB and we set the
Xmx to this value. But then the server crashed several times with
JVMCI015:OutOfMemoryError during our testing. We did some research and
found that lowering the heap size to 1536 prevented this problem. What
I want to understand exactly is why setting the max heap to 2048 caused
WebSphere to crash with JVMCI015:OutOfMemoryError. I understand that
lowering the heap is a good thing because it is better for GC to have a
smaller heap to clean, but what I need to be able to explain to our
customer exactly why changing the max heap from 2048 to 1536 prevents
the OutOfMemoryError.

Here is the exception stack trace:

[2/22/06 11:01:20:271 CST] 00000681 SystemErr R
java.lang.OutOfMemoryError: JVMCI015:OutOfMemoryError, cannot create
anymore threads due to memory or resource constraints
at java.lang.Thread.start(Native Method)
at com.ibm.ws.util.ThreadPool.addThread(ThreadPool.java:624)
at com.ibm.ws.util.ThreadPool$3.run(ThreadPool.java:1086)
at java.security.AccessController.doPrivileged1(Native Method)
at
java.security.AccessController.doPrivileged(AccessController.java(Compiled
Code))
at
com.ibm.ws.security.util.AccessController.doPrivileged(AccessController.java(Inlined
Compiled Code))
at com.ibm.ws.util.ThreadPool.execute(ThreadPool.java(Compiled Code))
at com.ibm.ws.util.ThreadPool.execute(ThreadPool.java(Compiled Code))
at
com.ibm.ws.management.event.NotificationDispatcher.sendTrInSeparateThread(NotificationDispatcher.java(Inlined
Compiled Code))
at
com.ibm.ws.management.event.NotificationDispatcher.sendWarningInSeparateThread(NotificationDispatcher.java(Inlined
Compiled Code))
at
com.ibm.ws.management.event.NotificationDispatcher$DispatchANotificationToAListener.run(NotificationDispatcher.java(Compiled
Code))
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java(Compiled
Code))

Our enviroment :
Websphere v6.0.2
Windows 2003
DB2 v8.2

Thanks
Prashanth