Volume recovery and restore

Volume recovery refers to the process of recovering a level 0 volume to its original condition as of a specified date. Volume recovery is typically necessary only after a complete volume has been damaged.

Four methods exist for DFSMShsm volume recovery:
  • Full-volume restore with update from incremental backup versions
  • Full-volume restore
  • Volume recovery from incremental backup versions
  • Volume recovery with the fast replication function

Because full-volume restore with update is somewhat a combination of the other two methods, and therefore the most complete, it is discussed first.

When recovering volumes by using backup versions either for update or as the only source, DFSMShsm provides optimized tape usage. The optimization is accomplished by recovering all required data sets from each individual tape in priority order with a single tape mount.

When recovering volumes by using backup versions either for update (APPLYINCREMENTAL) or as the only source, DFSMShsm recovers all cataloged non-VSAM data sets—whether they are SMS-managed—and all cataloged VSAM non-SMS-managed data sets to the volume being recovered. DFSMShsm may recover VSAM SMS-managed data sets to other volumes in the same storage group as the volume being recovered.

The procedures for recovering an ML1 volume differ from those for recovering a level 0 volume. See Recovering a migration volume for a discussion of the procedures for ML1 volumes.

Attention: DFSMShsm incremental recovery and volume restore with APPLYINCREMENTAL does not support a device type change on the volume being recovered. If the device type is changed after the volume is backed up and if the device type in the catalog for all data sets residing on the volume is not changed, all VSAM data sets will fail to be recovered. All non-VSAM data sets may appear to be recovered successfully, but the first allocation after the recovery will fail because of the inconsistent unit name and device type that were created by the recovery.