Disabling or enabling a high availability manager

A unique HAManagerService configuration object exists for every core group member. The enable attribute in this configuration object determines if the high availability manager is enabled or disabled for the corresponding process. When the enable attribute is set to true, the high availability manager is enabled. When the enable attribute is set to false, the high availability manager is disabled. By default, the high availability manager is enabled. If the setting for the enable attribute is changed, the corresponding process must be restarted before the change goes into effect.

Before you begin

Determine if you need to use a high availability manager to manage members of a core group.

Avoid trouble: When you disable the high availability manager, make sure that you disable it for all the servers in a core group so that all members are disabled. Do not disable the high availability manager for select members of the core group. For more information, see the following documents:
  • 2.1.6.1 High availability is not needed section of the Best Practices for Large WebSphere Topologies document
  • 6.3.3 Partitioned cell with HA manager-disabled core group topology section of the Techniques for Managing Large WebSphere Installations Redbooks publication.

About this task

You might want to disable a high availability manager if you are trying to reduce the amount of resources, such as CPU and memory, that the product uses and have determined that the high availability manager is not required on some or all of the processes in a core group.

You might need to enable a high availability manager that you previously disabled because you are installing applications on core group members that must be highly available.

Complete the following steps if you need to disable a high availability manager or to enable a high availability manager that you previously disabled.

Procedure

  1. In the administrative console, navigate to the Core group service page for the process.
    • For a deployment manager, click System Administration > Deployment manager > Core group service.
    • For a node agent, click System Administration > Node agent > node_agent > Core group service.
    • For an application server, click Servers > Server Types > WebSphere application servers > server_name > Core group service.
  2. If you want to disable the high availability manager for this process, deselect the Enable service at server startup option.
  3. If you want to enable the high availability manager for this process, select the Enable service at server startup option.
  4. Click OK and then click Review.
  5. Select Synchronize changes with nodes, and then click Save.
  6. Restart all of the processes for which you changed the Enable service at server startup property setting.

Results

The processes start with the high availability manager in the changed state.

What to do next

To verify that the high availability manager is in the proper state, check the log file for one of the following messages:

HMGR0005I: The Single Server DCS Core Stack transport has been started for core group DefaultCoreGroup.

This message indicates that the high availability manager is disabled because the high availability manager communication transport can only establish communication with a single server process.

HMGR0001I: The DCS Core Stack transport has been started for core group DefaultCoreGroup. There are x members.

This message indicates that the high availability manager is enabled because the high availability manager communication transport can establish communication with multiple server processes. x indicates the number of server processes with which communication is established.