Restarting a quiesced system requires help from an active system — a system that is currently actively participating in the global resource serialization complex. The active system provides current information about global resource requests. A quiesced system does not have this current information. For this reason, a quiesced system cannot make itself an active system without introducing a data integrity exposure.

In contrast, an inactive system has current information about the requests and can make itself an active system without introducing a data integrity exposure.

Under normal conditions, including most ring disruptions, at least one system is active and can restart a quiesced system, or an inactive system can make itself active and can restart a quiesced system.

Under unusual conditions, all systems in the complex might be either quiesced or failed. This condition can occur when the operators quiesce all but one system and then the only active system fails. When all systems are quiesced or have failed, an installation can recover the complex in two ways:

1. Perform a complex-wide IPL. This process is cumbersome and time-consuming, particularly when MVS™ is still running on the quiesced systems.
2. Allow global resource serialization to reactivate a system. Reactivating a system means turning a quiesced system into an active system. It avoids the complex-wide IPL but can introduce data integrity exposures or other problems related to global resources.

Reactivating a system is less disruptive than a complex-wide IPL. Careful planning for the process can reduce the impact of the data integrity exposure.

The recovery procedure shows how to reactivate a four-system complex. The procedure assumes a four-system complex, SYS1, SYS2, SYS3, and SYS4. The following events occurred:

1. At 10:00, the operator entered VARY GRS(*),QUIESCE on SYS4.
2. At 10:01, the operator entered VARY GRS(*),QUIESCE on SYS3.
3. At 10:02, the operator entered VARY GRS(*),QUIESCE on SYS2.
4. At 10:03, the only remaining active system SYS1, failed.