FreeKB - Respond to a WebSphere out of memory heap dump on Linux
Respond to a WebSphere out of memory heap dump on Linux

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Get the PID

If a heap dump is unexpectedly or automatically created, ensure that the JVM associated with the heap dump is still running properly. The heap dump files can be used to determine the PID associated with the heap dump, and then the PID can be used to determine the JVM associated with the heap dump. The heap dump files are in this format:

heapdump.<date>.<time>.<pid>.phd 

 

Is the PID in use

Let's say the PID is 12345. The ps command can be used to determine if the PID is still associated wth the JVM. In this example, the output of the ps command only displays the grep command, which means that the PID is no longer in use, which means that the JVM that was associated with the PID is no longer running, or was automatically restarted as part of the heap dump. If there is a significant amount of output, the JVM is still running. However, the JVM is probably in a bad way. For example, the JVM may be out of memory.

~]# ps -ef | grep 12345
root  12345  1  0  21:54  pts/0  00:00:00  grep 12345

 

Kill the PID if in use

When the JVM is in a bad way, you first will want to kill the PID, and the start the JVM.

~]# kill -9 12345

 

Determine the JVM associated with the PID

You can search the logs with the PID to determine what JVM was associated with the PID. This command will usually produce quite a bit of output, as this command searches every file at and below the specified directory for the string (12345 in this example). This may help you find the JVM that had the PID associated with the heap dump.

~]# grep -R /path/to/logs/directory -ie 'process id 12345'

 

The JVMs SystemOut.log can be used to know what PID the JVM is using (12345 in this example).

********** Start Display Current Environment **********
WebSphere Platform x.x.x.x running with process named cell\node\jvm and process id 12345

 

Start the application server

You can now start the application server.

 

Ensure the JVM is running

Once you know the JVM that had the PID with the heap dump, determine if the JVM was restarted. You can check the SystemOut.log file for the event "open for e-business" to determine when the JVM was last restarted.

~]# cat SystemOut.log | grep e-business
[2/1/18 4:27:32:991 CST] 0000001 WsServerImpl A WSVR0002I: Server server1 open for e-business; process id is 12345.

 

Check for out of memory

An OutOfMemory event may be in the SystemErr.log, native_stderr.log, or FFDC log before the heap dump event. Since this event may be in various logs, I like to use this command to search all of the logs.

grep -R /path/to/logs/directory -ie 'OutOfMemory'

 

If the out of memory event was captured in SystemErr.log, the type of memory that ran out of memory should be identified. 

java.lang.OutOfMemoryError: PermGen space
java.lang.OutOfMemoryError: Metaspace
java.lang.OutOfMemoryError: Java heap space
java.lang.OutOfMemoryError: GC overhead limit exceeded

 

PermGen / Metaspace

Java heap space

GC overhead limit exceeded

 

Check for hung threads

If there are hung threads, refer to this article.

grep -R /path/to/logs/directory -ie 'WSVR0605W'

 

 

 



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