Procedure

1. Alter the PARIS queue manager

In order for the application in Paris to be able to equally use the INVENTQ in Paris and the one in New York, we must inform the queue manager. On PARIS issue the following command:

ALTER QMGR CLWLUSEQ(ANY)

2. Review the inventory application for message affinities

Before proceeding, ensure that the inventory application does not have any dependencies on the sequence of processing of messages. See "Reviewing applications for message affinities" for more information.

3. Install the inventory application on the system in Paris

See the WebSphere MQ Application Programming Guide for information on how to do this.

4. Define the cluster queue INVENTQ

The INVENTQ queue which is already hosted by the NEWYORK queue manager is also to be hosted by PARIS. Define it on the PARIS queue manager as follows:

DEFINE QLOCAL(INVENTQ) CLUSTER(INVENTORY)

Now that you have completed all the definitions, make sure you have started the channel initiator on WebSphere MQ for z/OS, and, on all platforms, start a listener on queue manager PARIS. The listener listens for incoming network requests and starts the cluster-receiver channel when it is needed. See "Establishing communication in a cluster" for more information.

The cluster set up by this task looks like this:

Figure 25. The INVENTORY cluster, with three queue managers
The diagram shows the INVENTORY cluster, with NEW YORK, LONDON and PARIS connected inside the cluster. NEW YORK and LONDON are still hosting the inventory application, and NEW YORK and PARIS are hosting the INVENTQ.

The INVENTQ queue and the inventory application are now hosted on two queue managers in the cluster. This increases their availability, speeds up throughput of messages, and allows the workload to be distributed between the two queue managers. Messages put to INVENTQ by any of the queue managers LONDON, NEWYORK, PARIS are routed alternately to PARIS or NEWYORK, so that the workload is balanced.

The modification to this cluster was accomplished without you having to make any alterations to the queue managers NEWYORK or LONDON. The full repositories in these queue managers are updated automatically with the information they need to be able to send messages to INVENTQ at PARIS.