Understanding JVM Heap Size Settings

When you provision an Oracle Java Cloud Service instance and specify a compute shape, the JVM heap size for WebLogic Server and Load Balancer processes is determined automatically.

Default Heap Sizes

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

For the RAM and heap settings used in Oracle Java Cloud Service—Coherence instances, see About Default Capacity Units for Oracle Java Cloud Service—Coherence Instances.

The following table shows the Oracle Java Cloud Service JVM heap size settings for each compute shape.

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)

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)

Custom Heap Sizes

If you create an Oracle Java Cloud Service instance by using the REST API, you can specify a custom heap size for the JVMs in the service instance. See Create a Service Instance in REST API for Oracle Java Cloud Service. You cannot specify a custom heap size when creating a service instance with the web console.

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:

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.