This is related to a discussion I had with ataylor@redhat.com, when he was helping me with clustering.

Apparently, the broker does not load balance messages if they miss the application properties.

Steps to reproduce:

1. Configure a 3-node A-MQ 7.0.0 cluster
2. Send a message without any application properties (ie.: such as the ones sent by the messaging performance tool):

./mpt-sender perf -b amqp://host:5672/somequeue --log-level=debug -c 99 -p 1 -s 128 -N

Expected result: approximately 33 messages would be sent to each node on the cluster.

Actual result: all the messages (99) are retained on the node to which they are sent.

Work-around: send messages w/ application properties set (in this case, the messages are balanced among the nodes)