Tuning the JVM server startup environment

If you are running multiple JVM servers, you can improve performance by tuning the JVM startup environment.

About this task

When a JVM server starts, the server has to load a set of libraries in the /usr/lpp/cicsts/cicsts52/lib directory. If you start a large number of JVM servers at the same time, the time taken to load the required libraries might cause some JVM servers to time out, or some JVM servers might take an excessively long time to start. To reduce JVM server startup time, you should tune the JVM startup environment.

Procedure

  1. Create a shared class cache for the JVM servers to load the libraries a single time.
    To use a shared class cache, add the -Xshareclasses option to the JVM profile of each JVM server. For more information see Class data sharing between JVMs.
  2. Increase the timeout value for the OSGi framework.
    The DFHOSGI.jvmprofile contains the OSGI_FRAMEWORK_TIMEOUT option that specifies how long CICS® waits for the JVM server to start and shut down. If the value is exceeded, the JVM server fails to initialize or shut down correctly. The default value is 60 seconds, so you should increase this value for your own environment.