Performing peer recovery

Peer recovery is the process of completing the work that was left in an incomplete state due to the failure of an instance of DFSMStvs by another instance of DFSMStvs. The only function of peer recovery is to complete that work and then end; a peer recovery instance of DFSMStvs does not accept any new work.

Peer recovery occurs only in cases of system failure, not merely when DFSMStvs fails. These rules apply to peer recovery:

Peer recovery occurs only when both DFSMStvs and the system on which it was running fail. Peer recovery does not occur when the DFSMStvs instance failed, but the system continued to run. If this were the case, either DFSMStvs would automatically restart, or the DFSMStvs instance was stopped and was not meant to be restarted.
All resource managers that had shared interest in units of recovery restart on the same system. For this reason, DFSMStvs uses the automatic restart manager (ARM) to manage the grouping. If the installation is not using ARM, or if ARM is unavailable, you can manually initiate peer recovery by issuing the VARY SMS command, as follows:
```
VARY SMS,TRANVSAM(001),PEERRECOVERY,ACTIVE
```
Issue the VARY SMS command on another system. That system then runs peer recovery for the instance specified on the command, as well as any instances for which that instance was performing peer recovery.
Normally, if a DFSMStvs was disabling or disabled due to an operator command, peer recovery does not run. This is because that instance of DFSMStvs was told to come down and not restart. If you want peer recovery to occur, issue this command:
```
VARY SMS,TRANVSAM(001),PEERRECOVERY,ACTIVEFORCE
```
A peer recovery DFSMStvs instance is only started if there is a primary DFSMStvs instance of DFSMStvs running on the system. If DFSMStvs is not started on the system, peer recovery does not run.
Peer recovery starts asynchronous tasks to process outstanding units of recovery in parallel. As the tasks complete, additional tasks are started, until all the outstanding units of recovery are processed or an operator command is issued to request the end of peer recovery processing. If such a command is issued, tasks that are already running are allowed to complete, then peer recovery processing ends.
Peer recovery is allowed to run if the state of the failed DFSMStvs instance was quiescing, enabling, or enabled, since peer recovery would only complete the quiesce process. It is not allowed if the state was quiesced since, in this case, there should be no work to do. It also is not allowed if the state was disabled; this implies that the installation did not want the DFSMStvs instance to do any work. If you want peer recovery to be performed on behalf of a DFSMStvs instance that was disabling or disabled, you must use the VARY SMS command with the ACTIVEFORCE keyword.
If the DFSMStvs instance had been disabling due to an RRS failure, peer recovery is allowed to run. In this case DFSMStvs is reinitialized when RRS became available again.