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Unknown state of a cluster

Restore the cluster information in all the full repositories to a known state by rebuilding the full repositories from all the partial repositories in the cluster.


Problem

Under normal conditions the full repositories exchange information about the queues and queue managers in the cluster. If one full repository is refreshed, the cluster information is recovered from the other.

The problem is how to completely reset all the systems in the cluster to restore a known state to the cluster.


Solution

To stop cluster information being updated from the unknown state of the full repositories, all the CLUSRCVR channels to full repositories are stopped. The CLUSSDR channels change to inactive.

When you refresh the full repository systems, none of them are able to communicate, so they start from the same cleared state.

When you refresh the partial repository systems, they rejoin the cluster and rebuild it to the complete set of queue managers and queues. The cluster information in the rebuilt full is restored to a known state.

Note: 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 Refreshing in a large cluster can affect performance and availability of the cluster.
  1. On all the full repository queue managers, follow these steps:
    1. Alter queue managers that are full repositories so they are no longer full repositories.
    2. Resolve any in doubt CLUSSDR channels.
    3. Wait for the CLUSSDR channels to become inactive.
    4. Stop the CLUSRCVR channels.
    5. When all the CLUSRCVR channels on all the full repository systems are stopped, issue the command REFRESH CLUSTER(DEMO) REPOS(YES).
    6. Alter the queue managers so they are full repositories.
    7. Start the CLUSRCVR channels to re-enable them for communication.

  2. On all the partial repository queue managers, follow these steps:
    1. Resolve any in doubt CLUSSDR channels.
    2. Make sure all CLUSSDR channels on the queue manager are stopped or inactive.
    3. Issue the command REFRESH CLUSTER(DEMO) REPOS(YES).

Parent topic: Queue manager clusters troubleshooting

Last updated: 2020-10-04