MSCS and queue managers

Considerations concerning queue managers when using MSCS.

Create a matching queue manager on the other node

For clustering to work with IBM MQ, we need an identical queue manager on node B for each one on node A. However, we do not need to explicitly create the second one. We can create or prepare a queue manager on one node, move it to the other node as described in Moving a queue manager to MSCS storage, and it is fully duplicated on that node.

Default queue managers

Do not use a default queue manager under MSCS control. A queue manager does not have a property that makes it the default; IBM MQ keeps its own separate record. If you move a queue manager set to be the default to the other computer on failover, it does not become the default there. Make all the applications refer to specific queue managers by name.

Delete a queue manager

Once a queue manager has moved node, its details exist in the registry on both computers. When we want to delete it, do so as normal on one computer, and then run the utility described in Support for MSCS utility programs to clean up the registry on the other computer.

Support for existing queue managers

We can put an existing queue manager under MSCS control, provided that we can put your queue manager log files and queue files on a disk that is on the shared SCSI bus between the two machines (see Figure 1 ). We need to take the queue manager offline briefly while the MSCS Resource is created.

• Create a queue manager for use with MSCS
• Moving a queue manager to MSCS storage
• Put a queue manager under MSCS control

Telling MSCS which queue managers to manage

You choose which queue managers are placed under MSCS control by using the MSCS Cluster Administrator to create a resource instance for each such queue manager. This process presents you with a list of resources from which to select the queue manager that we want that instance to manage.

Queue manager log files

When you move a queue manager to MSCS storage, you move its log and data files to a shared disk (for an example see Moving a queue manager to MSCS storage ).

It is advisable before you move, to shut the queue manager cleanly and take a full backup of the data files and log files.

Multiple queue managers

IBM MQ MSCS support allows you to run multiple queue managers on each machine and to place individual queue managers under MSCS control.