The importance of IBM WebSphere MQ for clustered environments and load balancing

Suppose a customer has an important application that uses ibm®http://www.aliyun.com/zixun/aggregation/13387.html ">WEBSPHERE®MQ as a messaging system, You need to upgrade your existing distributed queuing environment to handle new business and ensure high availability. As part of the upgrade, some queue managers in an existing environment will be part of a cluster and some queue managers will be provided separately. This article will introduce a concept proof design proposed by IBM.

Queue Manager Alias definition

The Queue Manager alias definition has 3 uses:

Outgoing message: Remap Queue Manager name

The Queue Manager alias definition can be used to remap the queue manager name specified in a Mqopen call. For example, a Mqopen call specifies a queue name APPQ and a queue manager name Earth. The target Queue Manager has a Queue Manager alias definition similar to this:

This definition specifies that when an application puts a message into the Queue Manager Earth, the queue Manager that will be used is MARS. If the local queue manager is Earth, the message is placed in the local queue appq. If the name of the local queue manager is not Earth, the message is routed to a transmission queue named Mars by changing the transport header to indicate Mars rather than Earth.

Incoming message: Targeting

A received Message Channel agent (MCA) opens the queue referenced in the transport header. If there is a Queue Manager alias definition that has the same name as the referenced queue Manager, the Queue manager name received in the transport header is replaced with the rqmname from that definition. There are two uses for this mechanism:

as the local queue Manager

Outgoing messages: Modifying or specifying a transport queue

Figure 1 shows a scenario where the message arrives at the queue Manager QM1, and the transport header that displays the queue name arrives at the queue Manager QM3. QM3 will be reached via QM2 in Multi-hop (multi-hopping) mode:

Figure 1

All messages passed to QM3 are captured on QM1, where the queue Manager alias is QM3 and contains the definition QM3 through the transport queue QM2. This definition is similar to the following:

The queue Manager places messages on the transport queue QM2, but does not change the transport queue headers because the name of the target Queue Manager QM3 unchanged.

All messages that arrive at QM1 and display a transport header containing the queue name at QM2 are also placed on the QM2 transmission queue. In this way, messages with different targets are collected on a public transport queue for a suitable neighboring system for forwarding to their destinations.