Specifying the automatic recovery options, RESTART and REJOIN, means that operators seldom need to intervene to restart a system. When necessary, the operator on any system in the complex can issue the VARY GRS(sysname),RESTART command to bring the target system back into the ring. The target system can be either an inactive system or a quiesced system.

Restarting a system is the opposite of quiescing a system. VARY GRS(sysname),QUIESCE suspends global resource serialization and removes the target system from the ring. VARY GRS(sysname),RESTART resumes global resource serialization and brings the system back into the ring. The restarted system, because it is now part of the ring, can release any resources already freed by users and resume processing requests for global resources.

The VARY GRS(sysname),RESTART command can bring back into the ring a system that the operator had quiesced or a system that had become inactive or quiesced as a result of a ring disruption. After issuing the command, the operator can use D GRS to verify that the target system is now part of the ring.

There are three ways to issue the command. Issuing the first or second form of the command when all systems are inactive makes the specified system active, while all others become quiesced. The active system can then bring the other systems back into the ring.

1. VARY GRS(sysname),RESTART — issued from any active system to bring the named system back into the ring.
2. VARY GRS(*),RESTART — issued on the system to be restarted to bring that system back into the ring.
3. VARY GRS(ALL),RESTART — issued on any inactive system to restart the ring. Ensure that operators:
   • Allow automatic recovery processing to complete before issuing this command.
   • Issue this command only when there is no active system in the ring and at least one inactive system.
   • Issue this command only once during the process of recovery from a ring disruption.

   The command changes the state of all inactive systems from inactive to active. The command will not bring back systems that were quiesced before the ring disruption, such as those that the operator quiesced specifically.

Issuing any form of the command when all systems are quiesced invokes the reactivate function, which is designed for very unusual recovery situations.

To avoid the possibility of split rings, ensure that the operators issue VARY GRS(ALL),RESTART with extreme care.