Determine whether to use backup or dump versions for data set recovery

The non-DFSMShsm-authorized user has little control over whether a restore or a recover is done. The user’s ability to cause a physical data set restore rests with the options set for the dump classes and the dump volumes. Unless the user who issues a RECOVER or HRECOVER command specifies the GENERATION, VERSION, or DATE parameter, DFSMShsm tries to recover the most recent dump copy or backup version available (based on time of day and date).

The following conditions must exist for a data set restore to be performed instead of a recover of an incremental backup version when a RECOVER or HRECOVER command is issued:

The data set must be currently cataloged or must have been incrementally backed up by DFSMShsm at some time. If the data set is currently cataloged and no backup version exists for it, it must have been dumped from the volume it is cataloged on.
If FROMVOLUME is used to direct DFSMShsm to restore a data set from a dump copy, the dump copy made from the FROMVOLUME specified is used, regardless of the catalog status of the data set when the dump copy was made. The data set is restored to the FROMVOLUME specified and left uncataloged.
An eligible dump class must exist that allows individual data set restores (that is, the dump class must have the DATASETRESTORE attribute.)
The data set to be restored must have resided on a volume dumped to an eligible dump copy. See Searching for eligible dump copies for detailed information.
The dump volumes on which the dump copy resides must have a retention period other than NOLIMIT. DFSMShsm assumes that the dump volumes are physically available to be mounted when the RECOVER command is issued.
The data set must be listed in the dump VTOC copy data set associated with the dump generation in which the dump copy is contained.
The eligible dump copy must have been created more recently than the most recent incremental backup version. If a date is specified on the HRECOVER or RECOVER command, the recover is done from the backup version or dump copy that was performed before or on the specified date.
A specific generation or version must not have been requested. A generation for a data set refers only to the DFSMShsm incremental backup versions of the data set and not to the dump copies of the source volume.
The volume receiving the data set and the original volume from which the dump copy was made must be of similar device type.
The volume receiving the data set and the data set being restored must be compatible in terms of being SMS-managed. DFSMShsm will neither restore an SMS-managed data set to a non-SMS-managed volume, nor restore a non-SMS-managed data set to an SMS-managed volume.
The version of DFSMSdss installed must be at a sufficient level to support SMS.
The volume receiving the data set and the data set itself must both be SMS managed or non-SMS managed. DFSMShsm does not restore an SMS-managed data set to a non-SMS-managed volume, or a non-SMS-managed data set to an SMS-managed volume.

Note:

DFSMShsm always uses the backup version of SMS-managed, multiple-volume data sets unless you specify that the data set is to be restored from a dump copy.
See Restoring a data set from a DFSMShsm dump copy for a discussion of specifying data set restore from a dump copy.
Only an authorized user can specify restore from a dump copy.

If any of the conditions are not met, the HRECOVER or RECOVER process continues by attempting to find a DFSMShsm backup version to recover. If no DFSMShsm backup version exists, the HRECOVER or RECOVER request fails.

To further identify the backup version or dump copy you want to recover, specify a date or a relative generation number for the backup version. When you identify a backup or dump version with a date, DFSMShsm recovers the last version DFSMShsm created on or before the date you specified. When you identify a backup version with a generation number, the number represents the number of backup versions created before the most recent one. A GENERATION(0) indicates the most recently created backup version. If DFSMShsm requires access to a level 0 volume, daily backup volume, or spill backup volume during recovery and that volume is not online, DFSMShsm dynamically allocates the volume. If the backup version is on more than one tape volume, DFSMShsm allocates each required volume and the operator mounts each required volume.