IBM SC34-7012-01 manual Volume recovery procedure using CFVOL QUIESCE

There are several methods you can use to recover data sets after the loss of a volume. Whichever method you use (whether a volume restore, a logical data set recovery, or a combination of both), you need to ensure SMSVSAM puts data sets into a lost locks state to protect data integrity. This means that, after you have carried out the initial step of recovering the volume, your data recovery process must include the following command sequence:

1.ROUTE *ALL,VARY SMS,SMSVSAM,TERMINATESERVER

2.VARY SMS,SMSVSAM,FORCEDELETELOCKSTRUCTURE

3.ROUTE *ALL,VARY SMS,SMSVSAM,ACTIVE

The first command terminates all SMSVSAM servers in the sysplex and temporarily disables the SMSVSAM automatic restart facility. The second command (issued from any MVS) deletes the lock structure. The third command restarts all SMSVSAM servers, as a result of which SMSVSAM records, in the sharing control data set, that data sets are in lost locks state. The automatic restart facility is also reenabled.

Each CICS region detects that its SMSVSAM server is down as a result of the TERMINATESERVER command, and waits for the server event indicating the server has restarted before it can resume RLS-mode processing. This occurs at step 3 in the above procedure.

It is important to realize the potential impact of these commands. Deleting the lock structure puts all RLS-mode data sets that have retained locks, or are open at the time the servers are terminated, into the lost locks condition. A data set which is in lost locks condition is not available for general access until all outstanding recovery on the data set is complete. This is because records are no longer protected by the lost locks, and new updates can only be permitted when all shunted UOWs with outstanding recovery work for the data set have completed.

When CICS detects that its server has restarted, it performs dynamic RLS restart, during which it is notified that it must perform lost locks recovery. During this recovery process, CICS does not allow new RLS-mode work to start for a given data set until all backouts for that data set are complete. Error responses are returned on open requests issued by any CICS region that was not sharing the data set at the time SMSVSAM servers were terminated, and on RLS access requests issued by any new UOWs in CICS regions that were sharing the data set. Also, indoubt UOWs must be resolved before the data set can be taken out of lost locks state.

For RLS-mode data sets that are not on the lost volume, the CICS regions can begin lost locks recovery processing as soon as they receive notification from their SMSVSAM servers. For the data sets on these other volumes, recovery processing completes quickly and the data sets are removed from lost locks state.

For those data sets that are unavailable (for example, they are awaiting forward recovery because they are on the lost volume), CICS runs the backouts only when forward recovery is completed. In the case of CICSVR-managed forward recovery, completion is signalled automatically, and recovered data sets are removed from lost locks state when the associated backouts are run.

Volume recovery procedure using CFVOL QUIESCE

If a volume is lost and you logically recover the data sets using CICS VR, you do not need to use the CFVOL QUIESCE command (step 1 in the procedure described below).

190CICS TS for z/OS 4.1: Recovery and Restart Guide