About JVM Heap Settings

When you provision an Oracle Java Cloud Service instance and specify compute shapes, the Java Virtual Machine (JVM) heap size for WebLogic Server and Load Balancer processes is determined automatically.

Topics:

Default Heap Sizes

The compute shape you select for a WebLogic Server cluster determines the availability of RAM on the nodes in this cluster, and the amount of available RAM is used to determine the preset heap size for the JVM processes running on the nodes.

Different compute shapes are available for Oracle Java Cloud Service instances in Oracle Cloud Infrastructure and Oracle Cloud Infrastructure Classic regions.

The following table shows the Oracle Java Cloud Service JVM heap size settings for some of the available compute shapes.

Compute Shape	Min Heap Size	Max Heap Size	Configured Garbage Collector
OC3	256 MB	2 GB	default
OC4	256 MB	10 GB	Garbage First (-XX:+UseG1GC)
OC5	256 MB	24 GB	Garbage First (-XX:+UseG1GC)
OC6	256 MB	24 GB	Garbage First (-XX:+UseG1GC)
OC7	256 MB	24 GB	Garbage First (-XX:+UseG1GC)
OC1M	256 MB	10 GB	Garbage First (-XX:+UseG1GC)
OC2M	256 MB	24 GB	Garbage First (-XX:+UseG1GC)
OC3M	256 MB	24 GB	Garbage First (-XX:+UseG1GC)
OC4M	256 MB	24 GB	Garbage First (-XX:+UseG1GC)
OC5M	256 MB	24 GB	Garbage First (-XX:+UseG1GC)

Custom Heap Sizes

If you create an Oracle Java Cloud Service instance by using the REST API or CLI, you can specify a custom heap size for the JVMs in the service instance.

You cannot specify a custom heap size when creating a service instance with the web console. See Create a Service Instance in REST API for Oracle Java Cloud Service.

After provisioning a service instance, you can also change the heap size by using the WebLogic Server Administration Console. Refer to one of the following publications:

Increasing the heap size for a managed server in Administration Console Online Help (12.2.1.4)
Increasing the heap size for a managed server in Administration Console Online Help (12.2.1.3)
Set Java options for servers started by Node Manager in Administration Console Online Help (10.3.6) (specify the Java option to increase the heap size; for example: -Xmx3g)

The heap size is also set when you choose a shape for the load balancer. You cannot change the heap size for the load balancer.