IBM SC34-7012-01 manual Recovery of data set with volume still available, Quiesce the data set

Recovery of data set with volume still available

The procedure described here is necessary to preserve any retained locks that are held by SMSVSAM against the data in the old data set. Unless you follow all the steps of this procedure, the locks will not be valid for the new data set, with potential loss of data integrity.

The following steps outline the procedure to forward recover a data set accessed in RLS mode. Note that the procedure described here refers to two data sets—the failed data set, and the new one into which the backup is restored. When building your JCL to implement this process, be sure you reference the correct data set at each step.

1. Quiesce the data set

To prevent further accesses to the failed data set, quiesce it using the CEMT, or EXEC CICS, SET DSNAME QUIESCED command.

2. Create a new data set

Create a new data set into which the backup is to be restored. At this stage, it cannot have the same name as the failed production data set.

3. Issue FRSETRR

Use this access method services SHCDS subcommand to mark the failed data set as being subject to a forward recovery operation. This makes the data set unavailable to tasks other than those performing recovery functions, and also allows the following unbind operation to succeed.

4. Issue FRUNBIND

Use this access method services SHCDS subcommand to unbind any retained locks against the failed data set. This enables SMSVSAM to preserve the locks ready for re-binding later to the new data set used for the restore. This is necessary because there is information in the locks that relates to the old data set, and it must be updated to refer to the new data set. Unbinding and re-binding the locks takes care of this.

Note: You can include the access method services SHCDS FRSETRR and FRUNBIND subcommands of steps 3 and 4 in the same IDCAMS execution, but they must be in the correct sequence. For example, the SYSIN input to IDCAMS would look like this:

//SYSIN DD *

SHCDS FRSETRR(old_dsname) SHCDS FRUNBIND(old_dsname) /*

5. Restore the backup

After the unbind, restore a full backup of the data set to the new data set created in step 2. You can use the recovery function (HRECOVER) of DFSMShsm™ to do this.

6. Issue the FRSETRR subcommand

Use this access method services SHCDS subcommand to mark the new data set as being subject to a forward recovery operation. This is necessary to allow the later bind operation to succeed.

7. Run the forward recovery utility

Run your forward recovery utility to apply the forward recovery log to the restored data set, to redo all the completed updates.

8. Delete the old data set

Delete the old data set to enable you to rename the new data set to the name of the failed data set.

188CICS TS for z/OS 4.1: Recovery and Restart Guide