The members of a service integration bus are the application servers and server clusters within which messaging engines for that bus can run.
Adding a bus member automatically creates a messaging engine for that bus member. Each messaging engine has its own data store, used for example to store persistent messages and maintain durable subscriptions. By default a messaging engine associated with a server is configured with an in-process, Cloudscape-based data store. In other cases, you are asked to provide the Java Naming and Directory Interface (JNDI) name of a Java Database Connectivity (JDBC) data source for use by the messaging engine.
You can assign a queue destination to a bus member (that is, a server or a server cluster). If you do, each messaging engine in the bus member uses its data store to persist messages which are sent to that destination and which require persisting.
If required, you can remove members from a bus. However this action will delete any messaging engines associated with a bus member, including knowledge of any messages held by the data stores for those messaging engines. Careful planning is therefore recommended.
When a bus member is deleted, the data source associated with this bus member is not automatically deleted, because users often associate their own data source with a bus member. This also applies to bus members created using the default data source: the data source is not automatically deleted and must be manually removed. If you don't manually delete the data source, although the messaging bus member is created, the messaging engine will fail to start.