You can add extra messaging engines to a cluster bus member, for example to provide high availability or scalability in a cluster.
When you add a server or cluster as a member of a bus, at least one messaging engine is created automatically. Each server bus member has only one messaging engine. However, cluster bus members can support additional messaging engines.
You can add multiple messaging engines at the time you create the cluster bus member, or you can add extra messaging engines at a later time.
When you add an extra messaging engine to an existing cluster bus member, the flow of messages through existing messaging engines is not disrupted. Also, if dynamic reloading is enabled (by selecting the Configuration reload enabled property for the cluster bus member), the existing messaging engines do not have to be restarted to become aware of the new messaging engine.
For more information about configuring bus properties, see Configuring bus properties.