MustGather: Out of Memory exceptions on HP-UX, Part 1
 Technote (troubleshooting)
 
Problem(Abstract)
MustGather for troubleshooting WebSphere® Application Server java.lang.OutOfMemory exceptions on HP-UX. Gathering this information before calling IBM® support will help familiarize you with the troubleshooting process and save you time.
 
Cause
Two conditions can cause a java.lang.OutOfMemory exception:
  • The Java™ virtual machine (JVM) might run out of Java heap space to allocate a Java object.

  • The JVM might not be able to allocate the native memory that it needs to create or execute its threads.
 
Resolving the problem
If you have already contacted support, continue on to the component-specific MustGather information. Otherwise, refer to MustGather: Read first for all WebSphere Application Server products.


Out of Memory specific MustGather information

Out of Memory (heap leak) specific MustGather information
Debugging the JVM that is running out of Java heap.

If you suspect a memory leak in the Java heap, the first step is to eliminate any misconfiguration or tuning as a potential cause:
  1. Ensure that the heap generations (NEW and PERM) are sized appropriately. Default values for MaxPermSize (Permanent Region) are often insufficient for applications. The Permanent Region holds class data and other very long lived resources. MaxPermSize (default 64 MB) should be set to a quarter of the max heap.

    For example:

    -XX:MaxPermSize=128m

    MaxNewSize, the Young generation is intended for short-lived objects where Java objects are created and age, from where they are collected without a Full garbage collection (GC) cycle. Young Generation (default 32 MB) of the heap should be set to a quarter of max heap size. This option should only be used on the 1.3.1 JDK version.

    For example:

    -XX:MaxNewSize=128m

    For information on setting these properties, please see the Generic JVM Arguments section of the following document:

  2. Run in HotSpot Server mode (-server). Running in HotSpot client mode halves the size of the Permanent Region and therefore increases the stress on this part of the heap in the Sun JVM.

    For more details read, Setting up a HotSpot server or client mode on a Java 2 SDK.
  3. Also enable the following:

    -Xverbosegc:file=Xverbosegc.out

    Note: For more instructions, see Enabling verbosegc in WebSphere Application Server

  4. Stop the WebSphere application Server and recycle the logs
  5. Restart the application server.

  6. Run the application until java.lang.OutOfMemory exceptions occur.

  7. Collect the following information:
    • Xverbosegc.out
For WebSphere V6.0 and V6.:
  • All files in the following directory:

    install_root/profiles/profile_name/logs/server_name

  • All files in the following directory:

    install_root/profiles/profile_name/logs/ffdc

  • A copy of server.xml located in the following directory:

    install_root/profiles/profile_name/config/cells/
    cell_name
    /nodes/node_name/servers/server_name

  • Include all of the files from the following directory:

For WebSphere V5.0 and V5.1:
  • Include all of the files from the following directory:

    install_root/logs/server_name

  • All files in the following directory:

    install_root/logs/ffdc

  • A copy of server.xml located in the following directory:

    install_root/config/cells/cell_name/nodes/
    node_name
    /servers/server_name



Note: For all versions, If you have configured the application server to write logs into a different location, send them accordingly.

Follow instructions to Submitting Diagnostic Information to IBM Technical Support for Problem Determination.

For a listing of all technotes, downloads, and educational materials specific to the Out of Memory component, search the WebSphere Application Server support site.
 
Related information
Enabling verbosegc in WebSphere
Interpreting -Xverbosegc output
HPjmeter
Submitting information to IBM support
Steps to getting support
MustGather: Read first
Troubleshooting guide
 
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > Out of Memory
Operating system(s): HP-UX
Software version: 6.1
Software edition:
Reference #: 1164686
IBM Group: Software Group
Modified date: Feb 14, 2007