Configuring the k-cluster using heapdump
 Technote (troubleshooting)
 
Problem(Abstract)
HeapAnalyzer can be used to determine an appropriate k-cluster value for your JVM, providing a healthier java heap
 
Cause
HeapAnalyzer, available on www.alphaworks.ibm.com for analyzing Java™ heap dumps, can be used with a heapdump to determine an appropriate k-cluster value for your JVM.
 
Resolving the problem
1) After loading the heapdump into HeapAnalyzer, you will first be presented with a window giving a summary of the heapdump. Six lines down the recommended k-cluster is displayed (and highlighted below).


2) Using the k-cluster value above, in this example 31203, modify your k-cluster value by adding the following to your generic JVM arguments.

-Xknnnn

Where nnnn specifies the maximum number of classes the kCluster contains. -Xk instructs the JVM to allocate space for nnnn class blocks in kCluster.

IBM recommends that you add about 10% to the reported value (for example: 31203 > 34400 ). In this example, -Xk34400 is a good setting.
 
Related information
Using HeapAnalyzer to analyze Java heap usage and detec
Heap Fragmentation with IBM JVMs
 
 
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): Windows
Software version: 6.0
Software edition:
Reference #: 1230492
IBM Group: Software Group
Modified date: Feb 15, 2006