Using Message Broker in a HA Environment

Previous to Message Broker 7, the Transaction ID (TID) store was standalone and specific to each individual Broker in your system architecture architecture.  This made building HA solutions difficult and potentially error prone.

As a result it was possible for an event to generate duplicate updates as a result of having two different TIDs for the same event in two different TID stores (one for each broker).  


With the introduction of Message Broker 7 support for a shared queue as the TID store was introduced.

This enables a shared TID store to support multiple brokers, by configuring the TID store on a single remote queue manager.

As all brokers use the same central TID Store,  each Message Broker can ensure transaction integrity and avoid duplicate event delivery in the event of a connection failure.

http://www.ibm.com/developerworks/websphere/library/techarticles/1203_agarwal/1203_agarwal.html