For XA connections, the Resource Adapter for JMS with WebSphere® Application Server must always connect to the same messaging engine in a bus. High availability is therefore an important consideration.
If you are using XA resources, a specific messaging engine must be targeted for connection to allow indoubt transactions to be recovered, if this becomes necessary. Therefore, the availability of the messaging engine is critical to the ability of the Resource Adapter for JMS with WebSphere Application Server to connect to the bus. It is recommended that in this scenario the target messaging engine be made highly available by deploying it to a cluster so that in the event of a server failure the messaging engine will be failed over to an alternative server in the cluster.
This restriction does not apply to connections with no transactional context, or with local transactional context because in this case the transaction is always committed or rolled back immediately and there is therefore never an indoubt state.