Starting PowerHA SystemMirror cluster services with manually managed resource groups

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Set the cluster services Manage Resource Group startup option to Manually when you want more control over the node on which an application should run. This method ensures that the services provided by the application controller are not interrupted.

About this task

When you choose this option to start the PowerHA® SystemMirror® cluster services, the resource groups on the node remain in the OFFLINE or UNMANAGED state, depending on whether this is a cold start up or a start after the node was stopped and resource groups placed in an UNMANAGED state.

Note: Please be advised that if a resource group is in the UNMANAGED state, it does not mean that, from PowerHA SystemMirror's point of view, the actual resources in the resource group are not running. To PowerHA SystemMirror, it means that PowerHA SystemMirror is not managing the resources (and the applications) of the resource group for availability.

Note that either you must have an application monitor configured that PowerHA SystemMirror uses to check the application or your application start scripts should be intelligent enough not to start the application if it is already running.

If you want to activate resource groups that are not brought online automatically, use the Resource Group Management utility (clRGmove) to bring the OFFLINE state resource groups to the ONLINE state.

Consider the following example: If an application is running on a node that is not the primary node, and during the startup process you know that PowerHA SystemMirror will move the resource group with the application to another node (according to the resource group policy specified), starting PowerHA SystemMirror cluster services with the Manage Resource Group option set to Manually tells PowerHA SystemMirror not to start the resource groups during startup. You can later use the user-requested rg-move to bring the resource group to the ONLINE state on the same node where your application is already running.

To start cluster services on a resource group that is manually managed:

Procedure

  1. Enter smitty sysmirror
  2. System Management (C-SPOC) > Resource Group and Applications > Bring Resource Group Online.
  3. Select the node where your application is running.
  4. Press Enter.