Use this task to enable automated heap dump generation.
This function is not supported when using a Sun Java virtual machine (JVM) which includes WebSphere® Application Server
running on HP-UX and Solaris operating systems. You need to research
taking heap dumps on Sun JVMs or call IBM® Support.
Before you begin
Although heap dumps are only generated in response to a detected
memory leak, you must understand that generating heap dumps can have
a severe performance impact on WebSphere Application
Server for several minutes.
About this task
To
help you analyze memory leak problems when memory leak detection occurs,
some automated heap dump generation support is available.
To enable automated heap dump generation support,
perform the following steps in the administrative console:
Procedure
- Click Servers > Application
servers in the administrative
console navigation tree.
- Click server_name >Performance and Diagnostic Advisor Configuration.
- Click the Runtime tab.
- Select
the Enable automatic heap dump collection check
box.
- Click OK.
Results
The automated heap dump generation support
is enabled.
Important: To preserve disk
space, the Performance and Diagnostic Advisor does
not take heap dumps if more than 10 heap dumps already exist in the WebSphere Application Server
home directory. Depending on the size of the heap and the workload
on the application server, taking a heap dump might be quite expensive
and might temporarily affect system performance.
The automatic heap dump generation process dynamically
reacts to various memory conditions and generates dumps only when
it is needed. When the heap memory is too low, the heap dumps cannot
be taken or the heap dump generation cannot be complete.
What to do next
You can monitor any notifications of
memory leaks by checking the
SystemOut.log file or Runtime
Messages. For more information, see the
Viewing the Performance and Diagnostic Advisor recommendations topic. If a memory
leak is detected and you want to find the heap dump, refer to the
Locating and analyzing
heap dumps topic.
New feature: This topic
references one or more of the application server log files. Beginning
in WebSphere Application Server Version 8.0 you can configure the
server to use the High Performance Extensible Logging (HPEL) log and
trace infrastructure instead of using
SystemOut.log ,
SystemErr.log,
trace.log, and
activity.log files or native z/OS logging
facilities. If you are using HPEL, you can access all of your log
and trace information using the LogViewer command-line tool from your
server profile bin directory. See the information about using HPEL
to troubleshoot applications for more information on using HPEL.
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