Recover and restore processing

DFSMShsm recovers or restores a sequential extended format data set (indicated in the MCC record) using DFSMSdss as the data mover.

During full volume restore with APPLYINCREMENTAL, DFSMShsm does not apply the incremental backup version that is more recent than the full physical dump copy to a currently cataloged multiple-stripe sequential extended format data set. The stripe restored from the dump copy is scratched from the volume if the data set is no longer cataloged on the volume being processed.

During data set recovery of a multiple-stripe sequential extended format data set, without FROMDUMP(DUMPVOLUME(volser)) being specified, DFSMShsm always recovers an incremental backup version made by DFSMSdss, even if a physical full-volume dump copy is more recent than the incremental backup version. A message is issued to indicate that an incremental backup version has been recovered instead of a more recent dump copy.

During a recovery attempt of a multiple-stripe sequential extended format data set, when FROMDUMP(DUMPVOLUME(volser)) has not been specified, recovery fails if the data set has only been backed up by physical full-volume dump.

DFSMSdss restores a sequential extended format data set as follows:
  • A sequential extended format data set that was multiple-stripe when it was backed up or dumped can be recovered or restored as a multiple-stripe or single-stripe sequential extended format data set, regardless of the existence of the target data set before the RECOVER command is issued.

    The number of stripes depends on the storage class SUSTAINED DATA RATE value and the availability of the required volumes.

  • A sequential extended format data set that was single-stripe when it was backed up or dumped can be recovered or restored as a multiple-stripe or single-stripe sequential extended format data set, regardless of the existence of the target data set before the RECOVER command is issued.

    Again, the number of stripes depends on the storage class SUSTAINED DATA RATE value and the availability of the required volumes.

A sequential extended format data set that was either single-stripe or multiple-stripe when it was backed up or dumped is recovered or restored as a sequential extended format data set or non sequential extended format data set, regardless of the existence of the target data set before the RECOVER command is issued.

A data set that was not sequential extended format when it was backed up is always recovered or restored as a data set that is not sequential extended format. DFSMShsm does not convert a data set that is not sequential extended format to a sequential extended format data set through recovery or restore processing, even if the data set is preallocated as sequential extended format before the RECOVER command is issued.

If ACS filter routines are modified to direct a data set that was sequential extended format when it was backed up to a non-SMS-managed volume, the recovery or restore fails.

If FORCENONSMS is specified on the RECOVER command to force a sequential extended format data set to be recovered or restored to a non-SMS-managed volume, the data set will be recovered as a non sequential extended format data set. The maximum size of the non-SMS SAM data set is 1 volume.

If FROMVOLUME is specified on the RECOVER command to recover a sequential extended format data set, the recovery or restore fails.

If reblocking is required for a sequential extended format data set, DFSMShsm passes the requirement to DFSMSdss, which performs the reblocking.

To restore a single-stripe sequential extended format data set from a physical full volume dump tape, you can issue the RECOVER dsname FROMDUMP(DUMPVOLUME(volser)) command for the stripe dumped to the specified dump tape.

To restore an existing multiple-stripe sequential extended format data set from physical full volume dump tapes, you must issue the RECOVER dsname FROMDUMP(DUMPVOLUME(volser)) command for each stripe of the data set. If the sequential extended format data set no longer exists, you must catalog the data set after the restores, since DFSMSdss and DFSMShsm do not catalog a multiple-stripe sequential extended format data set during physical data set restore processing.

DFSMShsm fails the recovery of a sequential extended format data set if the desired backup version indicates that the data set was sequential extended format when it was backed up, and the data mover was DFSMShsm.
Note: DFSMShsm recovery or restore processing does not honor the “stripedness” specified in the data class DSNTYPE in the ACS filter routine. Changing the DSNTYPE definition or allocating the target data set before issuing the recover command has no effect on converting to or from striped data during DFSMShsm recovery or restore processing.

DFSMShsm does not recover a multiple-stripe sequential extended format data set during incremental full volume recovery.

If the target data set is preallocated and the REPLACE keyword is specified, DFSMShsm data set recovery, restore, incremental volume recovery, and full volume restore with APPLYINCREMENTAL processing delete the non-VSAM target data set, both SMS-managed and non-SMS-managed, before recovering or restoring the backup or dump copy.

DFSMShsm command data set recovery always lets DFSMSdfp select the target SMS-managed volume for a non-VSAM data set, even if the target data set is cataloged before the RECOVER command is issued. The volume the data set is cataloged on is still passed to DFSMSdfp, but the final target volume is selected by DFSMSdfp.