Suspending a queue manager from a uniform cluster

During normal operation of a uniform cluster, re-connectable client application instances might be automatically rebalanced at any time, to any queue manager in the cluster. If you want to prevent applications from connecting to a particular queue manager for a period of time, for example, during maintenance operations or problem determination, use the SUSPEND QMGR command.

Issue the command SUSPEND QMGR CLUSTER(uniform cluster name)

In addition to the usual effects of suspending from an IBM® MQ cluster, in a uniform cluster, the SUSPEND command also prevents re-connectable applications from being rebalanced to this queue manager.

Any such existing connections to the queue manager are immediately rebalanced to other available queue managers in the cluster when the command is issued.

Notes:

When queue managers are suspended from a cluster, DIS APSTATUS shows them as ACTIVE(NO), with the exception of the local queue manager, which always shows ACTIVE(YES) for its own status entry.
If all queue managers in the uniform cluster are suspended, applications remain connected to one or more of the suspended queue managers.

To avoid new connections being added to the queue manager being maintained, you should stop the server connection channel, or channels, used by your client applications, for example by issuing the following runmqsc command:

STOP CHANNEL(svrconn channel name)

This might not be possible if, for example, these channels are also used to connect administrative applications required during the maintenance window. For this reason, the suspended queue manager periodically checks for attached re-connectable applications

If any re-connectable applications are present, they are rebalanced to other available queue managers in the cluster. Maintenance can now be performed on the suspended queue manager.

Note: Applications not considered movable are not affected by either the initial command or subsequent rescans, and remain connected to the suspended queue manager; see MOVCOUNT for more details.

To resume a suspended queue manager:

If required, start the server connection channel to resume accepting new application connections, by issuing the following command:
```
START CHANNEL(svrconn channel name)
```

Issue the following runmqsc command:

RESUME QMGR CLUSTER(uniform cluster name)

The queue manager resumes communication with the rest of the uniform cluster and, if required to restore balance, re-connectable client application instances are redirected to this queue manager.