Refreshing a cluster queue manager

You can remove auto-defined channels and auto-defined cluster objects from the local repository using the REFRESH CLUSTER command. No messages are lost.

Before you begin

You might be asked to use the command by your IBM® Support Center. Do not use the command without careful consideration. For example, for large clusters use of the REFRESH CLUSTER command can be disruptive to the cluster while it is in progress, and again at 27 day intervals thereafter when the cluster objects automatically send status updates to all interested queue managers. See Clustering: Using REFRESH CLUSTER best practices.

About this task

A queue manager can make a fresh start in a cluster. In normal circumstances, you do not need to use the REFRESH CLUSTER command.

Procedure

Issue the REFRESH CLUSTER MQSC command from a queue manager to remove auto-defined cluster queue manager and queue objects from the local repository.

The command only removes objects that refer to other queue managers, it does not remove objects relating to the local queue manager. The command also removes auto-defined channels. It removes channels that do not have messages on the cluster transmission queue and are not attached to a full repository queue manager.

Results

Effectively, the REFRESH CLUSTER command allows a queue manager to be cold-started with respect to its full repository content. IBM MQ ensures that no data is lost from your queues.