If you decide to back up the control data sets and journal data set to DASD, you must first allocate and catalog a backup data set for each backup version of the control data sets. If the CDS is multicluster, additional backup version data sets are required. See Considerations when using multicluster control data sets.
The following example describes the process of backing up the control data sets and journal data set to multiple DASD backup data sets. The example assumes you have single-cluster control data sets.
SETSYS CDSVERSIONBACKUP(DATAMOVER(DSS) -
BACKUPCOPIES(3) -
BACKUPDEVICECATEGORY(DASD) -
MCDSBACKUPDSN(BHSM.MCDS.BACKUP) -
BCDSBACKUPDSN(BHSM.BCDS.BACKUP) -
OCDSBACKUPDSN(BHSM.OCDS.BACKUP) -
JRNLBACKUPDSN(BHSM.JRNL.BACKUP))
BACKUPCOPIES(3) indicates the number of preallocated data sets for each backup data set.
Copy Number | Names of Allocated Backup Data Sets |
---|---|
1 | BHSM.MCDS.BACKUP.V0000001 BHSM.BCDS.BACKUP.V0000001 BHSM.OCDS.BACKUP.V0000001 BHSM.JRNL.BACKUP.V0000001 |
2 | BHSM.MCDS.BACKUP.V0000002 BHSM.BCDS.BACKUP.V0000002 BHSM.OCDS.BACKUP.V0000002 BHSM.JRNL.BACKUP.V0000002 |
3 | BHSM.MCDS.BACKUP.V0000003 BHSM.BCDS.BACKUP.V0000003 BHSM.OCDS.BACKUP.V0000003 BHSM.JRNL.BACKUP.V0000003 |
When using RLS in a multiple DFSMShsm-host environment, DFSMShsm does an exclusive enqueue rather than a reserve.
When DFSMShsm backs up the control data sets and journal data set, it determines the final qualifier of the backup data sets. If the version number in the final qualifier matches the version number in the final qualifier of an existing data set, DFSMShsm uses the existing data set. In this example, DFSMShsm finds an existing backup data set the first three times it backs up the control data sets, and changes the first letter of the last data set name qualifier from V to D (V0000001 becomes D0000001). The fourth time DFSMShsm backs up the control data sets, it cannot find an existing version 4 backup data set. Therefore, DFSMShsm backs up the control data sets to the backup data set with the final qualifier of D0000001.
If you change the specification for the number of backup copies kept to increase the number of copies, you must first allocate and catalog additional backup data sets. Start with a final qualifier that is one more than the last final qualifier of your backup data sets on DASD.
For more information about allocating the MCDS, BCDS, OCDS, and journal data set, and their backup copies, see z/OS DFSMShsm Implementation and Customization Guide.