Messaging engines

Each service integration server or cluster bus member contains a component called a messaging engine that processes messaging send and receive requests and that can host destinations.

When you add an appserver or a server cluster as a bus member, a messaging engine is automatically created for this new member. If you add the same server as a member of multiple buses, the server is associated with multiple messaging engines (one messaging engine for each bus). If the bus member is a server cluster, it can have additional messaging engines to provide high availability or workload sharing characteristics. If the bus member is a WebSphere MQ server, it does not have a messaging engine, but it lets you access WebSphere MQ queues directly from WebSphere MQ queue managers and (for WebSphere MQ for z/OS) queue-sharing groups.

To host queue-type destinations, the messaging engine includes a message store where, if necessary, it can hold messages until consuming applications are ready to receive them, or preserve messages in case the messaging engine fails. There are two types of message store, file store and data store. For further information, see Administer message stores. Messaging engines are given a name which is based on the name of the bus member. Each messaging engine also has a universal unique identifier (UUID) that provides a unique identity for the messaging engine.

If you delete and recreate a messaging engine, it will have a different UUID and will not be recognized by the bus as the same engine, even though it might have the same name. For example, the recreated messaging engine will not be able to access the message store that the earlier instance used. If you accidentally delete a messaging engine configuration, and save the updated incorrect configuration, restore the configuration from a previous configuration backup.    

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Last updated Nov 10, 2010 8:23:07 PM CST