Set the JVM Heap Size

You can change the default JVM heap size for the Administration Server and Managed Servers by setting the USER_MEM_ARGS parameter in the startup script for Oracle WebLogic Server.

The following procedure sets the same values for both the Administration Server and Managed Servers.

See Administering Server Startup and Shutdown for Oracle WebLogic Server.

  1. Use the WebLogic Server Administration Console to shut down the servers.
  2. Open (or setDomainEnv.bat on Windows systems) for editing. You can create this file in:


  3. Set the -Xmx argument for USER_MEM_ARGS
    • Linux shell script (.sh)

      USER_MEM_ARGS="-Xms256m -Xmx1024m -XX:CompileThreshold=8000 -xx:PermSize=128m -XX:MaxPermSize=512m"
    • Windows command script (.bat)

      set USER_MEM_ARGS="-Xms256m -Xmx1024m -XX:CompileThreshold=8000 -xx:PermSize=128m -XX:MaxPermSize=512m"


    The arguments for USER_MEM_ARGS can vary, depending on the JDK vendor.
  4. After setting the parameter, save and close the file, then restart the Administration Server and Managed Servers for the changes to take effect.
  5. In a scaled-out system, repeat these steps for each domain home.

    The settings are now copied over when you horizontally scale-out.