XRF is suitable for situations where you have a single IMS DB/DC system that requires very high system availability (greater than 99.5%). However, the second z/OS containing the tracking IMS system must be channel-attached to the z/OS system that the first IMS is running on. RSR is suitable for situations where you have one or more IMS subsystems running in a number of address spaces on a single z/OS system and you want to minimize data loss in a failure situation, but can tolerate outages of approximately one hour. RSR uses network connections between the two z/OS systems, so there are no restrictions on the distance separating them. |