Restoring a data set from a DFSMShsm dump copy

A DFSMShsm-authorized user can specifically request that a data set be restored from a dump copy rather than recovered from a backup version. The following commands specifically request that a data set be restored from a dump copy:

RECOVER dsname FROMDUMP
This form of the command restores the data set from the most recent dump copy. If a data set is cataloged with the same name as the data set being restored, the restore fails.
RECOVER dsname FROMDUMP(DUMPCLASS(class))
This form of the command restores the data set from the most recent dump copy made to the specified dump class. If a data set is cataloged with the same name as the data set being restored, the restore fails.
RECOVER dsname FROMDUMP(DUMPVOLUME(volser))
This form of the command restores the data set from a specific dump volume. The volume might not be the most recent dump copy. If a data set is cataloged with the same name as the data set being restored, the restore fails.
RECOVER dsname FROMDUMP(DUMPVOLUME(volser)) REPLACE
This form of the command restores the data set from a specific dump volume. The restored data set replaces the cataloged data set having the same name.
RECOVER dsname TOVOLUME(volser) UNIT(unittype) - FROMDUMP(DUMPGENERATION(dgennum))
This form of the command restores the data set to the specified volume from a specified generation of a dump volume.
RECOVER dsname FROMDUMP(DUMPVOLUME(volser)) - UNIT(unittype) TOVOLUME(volser)
This form of the command restores the data set from a specific dump volume. This command must be used to restore a data set from a former device type when a new volume of a similar device type—but having the same volume serial number—resides on the system (for example, a 3380 volume is replaced with a 3390 volume, the same volume serial number is retained, and the 3390 volume is running in a 3380 emulation mode). The recovery is supported only when the target device type is similar to the source device type from which the dump copy was made.

The FROMDUMP parameter of the RECOVER command directs that the data set be restored from a dump copy. If the dump copy starts in file 2 or beyond on a stacked dump tape, DFSMShsm supplies the file block ID for high-speed positioning to the start of the dump copy.

You can also specify a DATE parameter to direct DFSMShsm to restore the data set from a dump made on or before the specified day.

Non-VSAM data sets and non-key-range VSAM data sets cataloged in an integrated catalog facility catalog that can be restored within the restrictions of DFSMSdss can be restored by DFSMShsm. Key-range VSAM data sets can be recovered from backup versions, but cannot be restored from dump volumes. The DFSMShsm default for a dump class does not allow physical data set restores from dump volumes. You can allow DFSMShsm to perform restores by specifying the DATASETRESTORE parameter of the DEFINE DUMPCLASS command.

During the data set restore, the dump volumes must be mounted in the same order that they were written during the full-volume dump. The dump volumes are read until the desired data set is found. For a dump copy stacked on a dump tape, with its own unique data set name, the search for the data set starts in the file containing the dump copy. If the dump volume has more than one valid dump copy, the desired data set is not catalogued or is migrated, and the data set has no backup copy, you must use the SOURCEVOLUME(volser) parameter of the FROMDUMP parameter to tell DFSMShsm which dump copy to use.

To restore an SMS-managed, multivolume, non-striped data set from a full-volume dump copy, you must recover each segment of the data set to a non-SMS-managed volume. This is accomplished by issuing the RECOVER command with the FORCENONSMS parameter for each segment of the data set (you can use the TOVOLUME parameter to direct the recovery of the data set to a specific volume). After recovering each segment of the data set, you can catalog the data set as a multivolume, non-SMS data set using IDCAMS. To make the data set SMS-managed, you can copy or move the data set to SMS-managed volumes. The restoration of the data set is complete after the data set is cataloged. The data set is not cataloged by the recovery operation.

You can use the LIST command to ensure that a dump copy contains the data set to be restored. For example, you may need the list if you are not running the incremental backup function and the data set is no longer cataloged.

To request that a data set be specifically restored from a dump copy, the following conditions must be satisfied:

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. (You can override this restriction by using the FORCENONSMS parameter to restore an SMS-managed data set to a non-SMS-managed volume, and the TOVOLUME parameter to direct recovery to a specific volume.)
The FROMDUMP parameter must be specified.
If the DUMPVOLUME subparameter is not specified, the data set must be currently cataloged or must have been incrementally backed up by DFSMShsm at some point in time. There must also be a dump copy of the original source volume in the specified class.

If the DUMPCLASS subparameter or the DUMPVOLUME subparameter is specified with the RECOVER command, DFSMShsm does not enforce the DATASETRESTORE subparameter or the permanent retention restrictions of the DEFINE command for the dump class that the dump copy is associated with. Dump volume availability is the responsibility of the authorized user in these cases; therefore, be careful not to request a data set restore from a dump volume that is not in the on-site tape library.

Rules: If neither the DUMPCLASS subparameter nor the DUMPVOLUME subparameter is specified with the FROMDUMP parameter, then the following conditions must be met or the command fails:

The data set must be currently cataloged or must have been incrementally backed up by DFSMShsm at some time. (This condition is also necessary when DUMPCLASS is specified.)
An eligible dump class must exist that allows individual data set restores. For example, the dump class must have the DATASETRESTORE attribute defined for the class.
The data set to be restored must have resided on a volume dumped to an eligible dump copy, as described by Searching for eligible dump copies.
The dump volumes on which the dump copy resides must have a retention period other than NOLIMIT. DFSMShsm assumes 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. This condition must also be met even if DUMPCLASS is specified.