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 we add an application server or a server cluster as a bus member, a messaging engine is automatically created for this new member. If we 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 IBM MQ server, it does not have a messaging engine, but it lets we access IBM MQ queues directly from IBM MQ queue managers and (for IBM 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 we 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 we accidentally delete a messaging engine configuration, and save the updated incorrect configuration, we must restore the configuration from a previous configuration backup.
Subtopics
- Mechanisms for stopping messaging engines
- Message points
- Messaging engine communication
- Security for messaging engines
- Applications with a dependency on messaging engine availability
Related:
Mediations Configure messaging engines Configure messaging engine properties List the messaging engines defined for a server bus member List the messaging engines for a cluster bus member Add a messaging engine to a cluster Removing a messaging engine from a cluster List the messaging engines in a bus Add additional messaging engines to a cluster bus member Removing a messaging engine from a bus Create the database, schema and user ID for a messaging engine Starting a messaging engine Stopping a messaging engine Displaying the runtime properties of a messaging engine Manage messaging engines with administrative commands Messaging engine troubleshooting tips