Tuning the JVM

The IBM® WebSphere® Application Server is a Java™ based process and requires a Java virtual machine (JVM) environment to run and support IBM Sametime® Advanced. You can tune the Java runtime environment for performance by turning on verbose garbage collection and setting the heap size.

About this task

Note: The following instructions contain settings that were tested in IBM labs. These are just a starting point. Since your deployment might have a configuration unique to your site, these settings might require more adjustment.

Procedure

  1. From the Integrated Solutions Console, click Servers > Application Servers > stadvanced_server_name.
  2. Under Server Infrastructure, click Java and Process management > Process Definition.
  3. Under Additional Properties, click Java Virtual Machine.
  4. Set the following properties:
    • Set the Initial heap size field to 512 MB.
    • Set the Maximum heap size to 1536 MB.
  5. Select the Verbose garbage collection check box.
  6. In the Generic JVM arguments field, enter the following argument. 
     -Xgcpolicy:gencon
  7. Click OK, and click Save to save changes to the master configuration.
  8. Click Custom properties.
  9. Click New.
  10. Add the property com.ibm.websphere.security.util.authCacheMaxSize, with a value of 120000.
  11. If Sametime is clustered, repeat the preceding steps for each node of the cluster.