The old MQ Clustering guide was broken into two parts because it was confusing customers. This guide focuses on how to make fault tolerant messaging systems. It discusses master/slave topologies and different failover transports that clients can use to find a running broker.
Most of the content has already been reviewed, but since it has been substantially reorganized it should be looked at once more. The big areas of concern are details that are missing or confusing.
The book also contains information about the fabric discovery URL that needs a full review.
Deadline for inclusion in the 7.0 Beta is 3/20/12.