If the target data set exists, DFSMShsm deletes the existing data set. DFSMShsm passes the storage class name associated with the data set to SMS or DFSMSdss. SMS selects the volume and allocates the target data set on that volume. DFSMShsm or DFSMSdss then copies the backup version into the recovered data set.
The catalog status of a recovered generation data set (GDS) is dependent upon its catalog status before being recovered. If the GDS is not cataloged before recovery, its catalog status after recovery is DEFERRED. If the GDS is cataloged before recovery, its catalog status after recovery remains the same, with the following exception: when DFSMShsm is used as a data mover to recover a rolled-off GDS, the cataloged status of the GDS, after it is recovered, is DEFERRED. Use the IDCAMS ALTER ROLLIN command to change the status from DEFERRED to ACTIVE.
If the backup version spans multiple tape volumes, DFSMShsm issues a message to the operator asking if all necessary tapes are available. If they are not all available, DFSMShsm cannot recover the data set.
If DFSMShsm requires access to a level 0 volume, a daily backup volume, or a spill backup volume during recovery and if that volume is not on line, DFSMShsm dynamically allocates the volume. If the backup version is on more than one tape volume, DFSMShsm allocates a unit where the operator mounts each required volume.