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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. |
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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.
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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:
- 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 |
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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. |
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For example: |
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-XX:MaxNewSize=128m |
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For information on setting these properties, please see
the Generic JVM Arguments section of the following document:
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- 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.
- Also enable the following:
- Stop the WebSphere application Server and recycle the logs
- Restart the application server.
- Run the application until java.lang.OutOfMemory exceptions occur.
- Collect the following information:
For WebSphere V6.0 and V6.:
- All files in the following directory:
install_root/profiles/profile_name/logs/server_name |
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- All files in the following directory:
install_root/profiles/profile_name/logs/ffdc |
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- 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 |
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- 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 |
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- All files in the following directory:
- A copy of server.xml located in the following
directory:
install_root/config/cells/cell_name/nodes/
node_name/servers/server_name |
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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. |
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