Symptoms

Each time Confluence is started, although ps aux shows that Confluence only takes Xmx + XX:MaxPermSize of physical memory, the VM's memory usage will spike to a level near the limit of the VM's physical memory.

Cause

By default, Atlassian applications such as Confluence will not use more physical memory (RES) than the specified Xmx + XX:MaxPermSize in JAVA_OPTS. This is however, not true with applications hosted in OpenFire. OpenFire does not seem to respect the limits specified in JAVA_OPTS, it only does so with INSTALL4J_ADD_VM_PARAMS.

Resolution

• Shutdown Confluence

• Navigate to ConfluenceInstallationDirectory/bin and edit setenv.sh

• Add the following line:

  INSTALL4J_ADD_VM_PARAMS="-Xms256m -Xmx512m -XX:MaxPermSize=256m $JAVA_OPTS -Djava.awt.headless=true "
  
  export INSTALL4J_ADD_VM_PARAMS

  Set the Xmx, Xms and MaxPermsize based on your requirements

• Startup Confluence