RESET CLUSTER: Forcibly removing a queue manager from a cluster
Use the RESET CLUSTER
command to forcibly remove a queue manager from a
cluster in exceptional circumstances.
You are unlikely to need to use this command, except in exceptional circumstances.
RESET CLUSTER
command only from full repository queue
managers. The command takes two forms, depending on whether you reference the queue manager by name
or identifier.-
RESET CLUSTER(clustername ) QMNAME(qmname) ACTION(FORCEREMOVE) QUEUES(NO)
-
RESET CLUSTER(clustername ) QMID(qmid) ACTION(FORCEREMOVE) QUEUES(NO)
RESET CLUSTER
command is run.Specifying QUEUES(NO)
on a RESET CLUSTER
command is the
default. Specifying QUEUES(YES)
removes references to cluster queues owned by the
queue manager from the cluster. The references are removed in addition to removing the queue manager
from the cluster itself.
The references are removed even if the cluster queue manager is not visible in the cluster; perhaps because it was previously forcibly removed, without the QUEUES option.
You might use the RESET CLUSTER
command if, for example, a queue manager has
been deleted but still has cluster-receiver channels defined to the cluster. Instead of waiting for
WebSphere® MQ to remove these definitions (which it does
automatically) you can issue the RESET CLUSTER
command to tidy up sooner. All other
queue managers in the cluster are then informed that the queue manager is no longer available.
If a queue manager is temporarily damaged, you might want to tell the other queue managers in the cluster before they try to send it messages. RESET CLUSTER removes the damaged queue manager. Later, when the damaged queue manager is working again, use the REFRESH CLUSTER command to reverse the effect of RESET CLUSTER and return the queue manager to the cluster. If the queue manager is in a publish/subscribe cluster, you then need to issue the REFRESH QMGR TYPE(PROXYSUB) command to reinstate any required proxy subscriptions. See REFRESH CLUSTER considerations for publish/subscribe clusters.
Using the RESET CLUSTER
command is the only way to delete auto-defined
cluster-sender channels. You are unlikely to need this command in normal circumstances. The IBM® Support Center might advise you to issue the command to tidy
up the cluster information held by cluster queue managers. Do not use this command as a short cut to
removing a queue manager from a cluster. The correct way to remove a queue manager from a cluster is
described in Removing a queue manager
from a cluster .
Because repositories retain information for only 90 days, after that time a queue manager that was forcibly removed can reconnect to a cluster. It reconnects automatically, unless it has been deleted. If you want to prevent a queue manager from rejoining a cluster, you need to take appropriate security measures.
All cluster commands, except DISPLAY CLUSQMGR
, work asynchronously. Commands
that change object attributes involving clustering update the object and send a request to the
repository processor. Commands for working with clusters are checked for syntax, and a request is
sent to the repository processor.
The requests sent to the repository processor are processed asynchronously, along with cluster requests received from other members of the cluster. Processing might take a considerable time if they have to be propagated around the whole cluster to determine if they are successful or not.