Configuring JVM settings for the integration server

For IBM® Integration Bus, the default memory settings of the JVM are as follows:

• Minimum: 32 MB
• Maximum: 256 MB

The amount of Java heap that is required depends on the message flows, and in particular the amount of Java that they contain. Remember, some nodes such as the FileInput node, or the SAPInput node are written in Java. Therefore, different integration servers might require different Java heap settings, so the same values cannot be reused for every integration server.

A larger Java heap might be needed when there is a heavy requirement from the message flow logic, or from the nodes that are used within it. The best way to determine whether there is sufficient Java heap is to look at the resource statistics for the integration server to check the level of garbage collection.

• For batch processing, low garbage collection resource statistics is the target. A garbage collection resource statistic of 1% is ideal.
• For real-time processing, low pause times are the target. A low pause time of under 1 second is ideal.

For guidance on resource statistics, see Starting resource statistics collection in the online product documentation.

The IBM Integration Bus JVM heap settings can be changed with the mqsichangeproperties command. The following example increases the maximum JVM heap to 512 MB for the integration server IN_OUT, in the integration node PERFBRKR:

mqsichangeproperties PERFBRKR -o ComIbmJVMManager -e IN_OUT -n jvmMaxHeapSize -v 536870912