How does the system administrator benefit?

 

Overview

Using clusters leads to easier administration of a network. The table below shows four queue managers each with two queues. Let us consider how many definitions are needed to connect these queue managers using distributed queuing. Then we will see how many definitions are needed to set up the same network as a cluster.

 

Definitions to set up a network using distributed queuing

Description Number per queue manager Total number
A sender-channel definition for a channel on which to send messages to every other queue manager 3 12
A receiver-channel definition for a channel on which to receive messages from every other queue manager 3 12
A transmission-queue definition for a transmission queue to every other queue manager 3 12
A local-queue definition for each local queue 2  8
A remote-queue definition for each remote queue to which this queue manager wants to put messages 6 24

While you might reduce this number of definitions by, for example, using generic receiver-channel definitions, the maximum number of definitions could be as many as 20 on each queue manager, which is a total of 80 for this network.

 

Definitions to set up a network using clusters

When using clusters, you need:

To set up the network shown in Figure 3 using clusters you need the following definitions:

Table 2. Definitions for clustering

Description Number per queue manager Total number
A cluster-sender channel definition for a channel on which to send messages to a repository queue manager 1 4
A cluster-receiver channel definition for a channel on which to receive messages from other queue managers in the cluster 1 4
A local-queue definition for each local queue 2 8

To set up this cluster of queue managers (with two full repositories), you would need 4 definitions on each queue manager -- a total of 16 definitions all together. You would also need to alter the queue-manager definitions for two of the queue managers, to make them full repository queue managers for the cluster.

The CLUSSDR and CLUSRCVR channel definitions need be made only once. When the cluster is in place you can add or remove queue managers (other than the repository queue managers) without any disruption to the other queue managers.

Clearly, this amounts to a significant reduction in the number of definitions required to set up a network containing a large number of queue managers.

With fewer definitions to make there is less risk of error:

  • Object names will always match, for example the channel name in a sender-receiver pair.

  • The transmission queue name specified in a channel definition will always match the correct transmission queue definition or the transmission queue name specified in a remote queue definition.

  • A QREMOTE definition will always point to the correct queue at the remote queue manager.

Furthermore, once a cluster is set up, you can move cluster queues from one queue manager to another within the cluster without having to do any system management work on any other queue manager. There is no chance of forgetting to delete or modify channel, remote-queue, or transmission-queue definitions. You can add new queue managers to a cluster without any disruption to the existing network.