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Parameters to improve Maximo performance using WebSphere

Technote (troubleshooting)


Problem(Abstract)

Maximo and WebSphere recommendations for performance improvements relating to memory use.

Resolving the problem

IBM WebSphere changed parameters in the JDK in IBM JDK1.4.2 SR3. Any WebSphere version using IBM JDK 1.4.2 SR3 or greater is affected.
The change may cause WebSphere to hold onto unused objects for up to ten minutes after they are no longer needed. In high usage environments, this may act as a memory leak so that the application is starved for memory. There is a parameter to control this behavior, ackTimeout.

Some networks may also benefit from a parameter change in the JDK to set the default TCP/IP stack to V4. This can improve network performance by since the default behavior will be for the standard IP V4 and WebSphere will not need to determine the IP type programmatically. This parameter is -Djava.net.preferIPv4Stack.

The default value for the ackTimeout parameter is 600000 milliseconds or, 10 minutes.

The recommended setting is 10000 or 10 seconds

-Dsun.rmi.dgc.ackTimeout=10000

NOTE: Lowering this value has the effect of causing the server to check objects more often and could increase CPU utilization. Settings such as these often have a trade off. A balance of CPU utilization vs. memory clearing should be struck. The default settings are generally acceptable and these changes should only be made if performance and memory utilization issues occur.

The other parameter to improve the performance of TCP/IP V4 packets should also be set

-Djava.net.preferIPv4Stack=true

These parameters may be set in the WebSphere Admin Console under Application servers > {application name} > Process Definition > Java Virtual Machine
in the Generic JVM Argument field as shown below.

-Dsun.rmi.dgc.ackTimeout=10000 -Djava.net.preferIPv4Stack=true

Additional information on these and other JVM settings may be available at the following link:

WebSphere 5.1
http://publib.boulder.ibm.com/infocenter/wasinfo/v5r1/index.jsp?topic=/com.ibm.websphere.base.doc/info/aes/ae/urun_rconfproc_jvm.html

WebSphere 6.1
http://publib.boulder.ibm.com/infocenter/wasinfo/v6r1/index.jsp?topic=/com.ibm.websphere.base.doc/info/aes/ae/urun_rconfproc_jvm.html

WebSphere 7.0
http://pic.dhe.ibm.com/infocenter/wasinfo/v7r0/index.jsp?topic=/com.ibm.websphere.base.doc/info/aes/ae/urun_rconfproc_jvm.html

WebSphere 8.5.5
http://www-01.ibm.com/support/knowledgecenter/SSEQTP_8.5.5/com.ibm.websphere.base.doc/ae/urun_rconfproc_jvm.html?lang=en


Cross reference information
Segment Product Component Platform Version Edition
Systems and Asset Management Tivoli Asset Management for IT All
Systems and Asset Management Maximo Asset Management Essentials All
Systems and Asset Management Maximo Asset Management Essentials All
Systems and Asset Management Maximo Asset Management Essentials All

Historical Number

M05324

Product Alias/Synonym

MAXIMO

Document information

More support for: Maximo Asset Management

Software version: 5.2, 6.0, 6.1, 6.2, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.2.5, 6.2.6, 6.2.7, 6.2.8, 7.1, 7.1.1, 7.5, 7.6

Operating system(s): AIX, HP-UX, Linux, Windows

Reference #: 1261874

Modified date: 06 December 2007


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