Description of the illustration ha_symmetric.gif

This figure represents Symmetric High Availability Model supported by Messaging Server. In the figure, two Physical Nodes, where both Physical-A and Physical-B are Active nodes and serving as a backup node for each other. Each Physical node is seen controlling one disk array with two storage volumes. In the figure, you see Physical-A controlling one disk array with two storage volumes, where one volume is used for Physical-A's local Message store partitions and MTA queues, and the other is a mirror image of its partner Physical-B's message store partitions and MTA queues. Similarly, it is vice-versa for disk array controlled by Physical-B. When a failover occurs, the services on the failing node are shut down and restarted on the backup node. At this point, the backup node runs Messaging Server for both nodes and manages two separate volumes.