SELECTVOLUME: Specifying whether DFSMShsm should select a scratch tape volume or a DFSMShsm tape volume

Explanation: SELECTVOLUME is an optional parameter specifying whether DFSMShsm chooses a tape volume owned by DFSMShsm or a scratch tape volume when an end-of-volume (EOV) condition occurs while DFSMShsm is writing on a tape volume. SELECTVOLUME(SCRATCH | SPECIFIC) applies to the initial selection for dump tape volumes as well as to the EOV condition.

If you specify the global SELECTVOLUME(SCRATCH | SPECIFIC) parameter, the parameter applies to all functions (migration, backup, and dump). If you specify a specific volume type with the SELECTVOLUME(MIGRATION | BACKUP | DUMP) parameter, the parameter applies only to that type of function. If you specify a global value and a specific volume type in a single command, the command fails.

Subparameter	Explanation
SCRATCH	A PRIVAT mount request is always sent to the operator when an EOV condition occurs on a tape backup volume, tape migration level 2 volume, or dump tape volume. The operator should mount a private scratch tape volume.
SPECIFIC	DFSMShsm chooses another tape volume when an EOV condition occurs on a tape backup volume, tape migration level 2 volume, or dump tape volume. DFSMShsm chooses a tape volume you have already defined to DFSMShsm with the ADDVOL command. If the EOV condition occurs on a tape backup volume, DFSMShsm chooses another tape backup volume. If the EOV condition occurs on a tape migration level 2 volume, DFSMShsm chooses another tape migration level 2 volume. If the EOV condition occurs on a dump tape volume, DFSMShsm chooses another dump tape volume. DFSMShsm first attempts to select a dump tape volume that is assigned to the same class as is currently being dumped to. If a dump tape volume with the same class cannot be found, then DFSMShsm looks for a dump tape volume that is not assigned to any class. When DFSMShsm chooses the tape volume, the operator receives a message specifying which tape to mount. If DFSMShsm cannot find an acceptable tape volume, the operator receives a PRIVAT mount request.

Subparameter

Explanation

SCRATCH

A PRIVAT mount request is always sent to the operator when an EOV condition occurs on a tape backup volume, tape migration level 2 volume, or dump tape volume. The operator should mount a private scratch tape volume.

SPECIFIC

DFSMShsm chooses another tape volume when an EOV condition occurs on a tape backup volume, tape migration level 2 volume, or dump tape volume. DFSMShsm chooses a tape volume you have already defined to DFSMShsm with the ADDVOL command. If the EOV condition occurs on a tape backup volume, DFSMShsm chooses another tape backup volume. If the EOV condition occurs on a tape migration level 2 volume, DFSMShsm chooses another tape migration level 2 volume. If the EOV condition occurs on a dump tape volume, DFSMShsm chooses another dump tape volume. DFSMShsm first attempts to select a dump tape volume that is assigned to the same class as is currently being dumped to. If a dump tape volume with the same class cannot be found, then DFSMShsm looks for a dump tape volume that is not assigned to any class. When DFSMShsm chooses the tape volume, the operator receives a message specifying which tape to mount. If DFSMShsm cannot find an acceptable tape volume, the operator receives a PRIVAT mount request.

DFSMShsm distinguishes between devices that have the same logical device type but which have different physical devices. There are four types of 3490's:

Emulated on a 128 track device
Emulated on a 256 track device
Emulated on a virtual tape server (VTS) subsystem as a virtual tape volume
All others

There are three types of 3590's:

Native 128 track devices
Native 256 track devices
Native 384 track devices

DFSMShsm examines the technology of the restricting output unit name and prefers selecting a partially filled cartridge having that recording format, at initial selection for backup to tape or migration to tape. If no cartridge matching the recording technology is found, then a nonspecific mount is requested.

Note: If a specific volume is specified for output during initial or subsequent (end-of-volume) processing the following requirements apply:

If a library device is allocated:
- The tape volume must be in the library for it to be considered eligible for selection. If the tape volume is outside the library, it is marked unavailable in the DFSMShsm inventory.
- If a data class is assigned to the DFSMShsm tape data set name and the ACS COMPACTION attribute is specified (Y or N), the following considerations apply:
  - A partial tape is eligible for initial tape selection when the compaction status is consistent with the ACS data class COMPACTION attribute, and its device type is consistent with the allocated device type.
  - If a tape volume is empty, the existing selection rules related to device type eligibility still apply.
- If a data class is not assigned or a data class is assigned to the DFSMShsm tape data set name and the ACS COMPACTION attribute is not specified (blank), the following considerations apply:
  - A partial tape is eligible for initial tape selection when its device type is consistent with the allocated device type (the compaction status assigned to a partially full tape does not influence initial tape selection).
  - If a tape volume is empty, the existing selection rules related to device type eligibility still apply.
If a non library device is allocated, the tape volume must not be in a library for it to be considered eligible for selection. If the tape volume is in a library, it is marked unavailable in the DFSMShsm inventory.

SMS relationship: Parameter has the same meaning when applied to SMS-managed or non-SMS-managed DASD volumes or data sets.

SETSYS default: None.

DFSMShsm default: If you do not specify either parameter on any SETSYS command, the DFSMShsm default is SCRATCH.

Note:

Use the SCRATCH subparameter if you have the cartridge loader of the 3480 Magnetic Tape Subsystem. The cartridge loader provides the operator with the capability to preload multiple tapes used as migration, backup, or dump tapes. The system then writes migration data sets, backup data sets, or dump copies to these tapes without operator intervention.
The volume verification exit can reinitialize a tape volume if the tape remains under control of DFSMShsm. Therefore, to use the volume verification exit effectively, specify SPECIFIC and TAPEDELETION(HSMTAPE).
This parameter has no effect when aggregate recovery is recovering data sets to ML2 tape volumes. Aggregate recovery will always request the mount of a non specific (scratch) volume.
Repeating the SELECTVOLUME parameter for specific volume types in a single SETSYS command causes conflict. The last entered SELECTVOLUME parameter overrides all other SELECTVOLUME parameters in this single command and is the only parameter processed.
For example, if you enter the following command, only the SELECTVOLUME(DUMP(SCRATCH)) parameter is processed. The SELECTVOLUME(MIGRATION(SPECIFIC)) and the SELECTVOLUME(BACKUP(SCRATCH)) parameters are not processed and their DFSMShsm defaults are applied.
```
   SETSYS SELECTVOLUME(MIGRATION(SPECIFIC))  -
          SELECTVOLUME(BACKUP(SCRATCH))      -
          SELECTVOLUME(DUMP(SCRATCH))
```
To prevent this from happening, enter the command as follows. In this way, all of the parameters are processed.
```
   SETSYS SELECTVOLUME(MIGRATION(SPECIFIC)   -
                       BACKUP(SCRATCH)       -
                       DUMP(SCRATCH))
```
Another way to enter this command is to repeat the SETSYS command three times with different subparameters for the SELECTVOLUME parameter. Issuing the SELECTVOLUME command in this way allows you to group parameters together in separate sections of your PARMLIB member.
```
   SETSYS SELECTVOLUME(MIGRATION(SPECIFIC))
   SETSYS SELECTVOLUME(BACKUP(SCRATCH))
   SETSYS SELECTVOLUME(DUMP(SCRATCH))
```