TAPEMIGRATION: Specifying the type of migration to tape

Explanation

TAPEMIGRATION is an optional parameter specifying that you want DFSMShsm to use migration level 2 (ML2) tape volumes, to limit the selection and allocation of an output volume during tape migration processing, and to attempt fast subsequent migration.

The following are required or optional parameters of the TAPEMIGRATION parameter:

DIRECT

Data sets on DFSMShsm-managed primary volumes are migrated directly to ML2 tape volumes. If the primary volume is defined with the AUTOBACKUP attribute, data sets on the primary volume with the change flag set to 1 will not be migrated to an ML2 tape volume.

ML2TAPE

Data sets on ML1 volumes are migrated to ML2 tape volumes.

NONE

Data sets are not migrated to ML2 tape volumes unless migration to an ML2 tape volume is indicated by an external-to-DFSMShsm factor. An ML2 tape volume is selected when:

The ARCMDEXT exit is used to select migration to an ML2 tape volume from a primary volume (level 0).
An SMS-managed data set that belongs to a management class indicating that the data set is to be migrated directly to an ML2 tape volume.

ROUTETOTAPE

TAPE

Specify a tape volume.

ANY

Any available tape volume is selected. If no tape volumes are available, then the value of the SETSYS MIGUNITNAME system setting is used to allocate a scratch tape.

unittype

An ML2 tape volume that is compatible with the specified unit type is selected. If no tape volumes of that unit type are available, then a scratch tape of that unit type is selected.

The following are valid types of tape units:

3480
3480X
3490
3590-1

You can substitute an esoteric tape unit defined with the SETSYS USERUNITTABLE command. If you specify an esoteric tape unit name that does not exist in the user unit table, the command fails. If you specify:

3480 or 3480X, you use all the functions of the 3480 Magnetic Tape Subsystem.
3490, you use all the functions of the 3490 Magnetic Tape Subsystem.
3590-1, you use all the functions of the 3590 Magnetic Tape Subsystem.

RECONNECT

Data sets eligible for fast subsequent migration can be reconnected to the ML2 tape volume from which they were recalled. A data set can be reconnected if all fast subsequent migration requirements are satisfied. For more information about these requirements, see Fast subsequent migration (reconnection) eligibility requirements.

NONE: Data sets are not eligible for fast subsequent migration and are not reconnected to the ML2 tape volume from which they were recalled.
ALL: All data sets that are eligible for standard migration and satisfy fast subsequent migration eligibility requirements are reconnected to the ML2 tape volume the data set was recalled from; including data sets that would have otherwise been migrated to an ML1 volume.
ML2DIRECTEDONLY: Data sets that are eligible for direct migration to ML2 tape volumes and satisfy fast subsequent migration eligibility requirements are reconnected to the ML2 tape volume the data set was recalled from. Data sets not eligible for direct migration to ML2 tape volumes are processed using the standard migration method.

SMS relationship

The TAPEMIGRATION parameter applies in some instances to SMS-managed DASD volumes or data sets. SMS-managed data sets with the LEVEL 1 DAYS NON-USAGE = NOLIMIT management class attribute are specifically prohibited from migrating to tape.

Tape library relationship

A tape unit name can be used for filtering in the ACS routines. If you specify a unit type, it will be sent to the ACS routines in SMS for the tape migration function.

SETSYS default

If you specify:

DIRECT or ML2TAPE with no parameter, the default is TAPE(ANY).
DIRECT or ML2TAPE with TAPE but no parameter, the default is ANY.
NONE with no parameter, the default is ROUTETOTAPE(ANY).
NONE with ROUTETOTAPE but no parameter, the default is ANY.
RECONNECT with no parameter, the default is NONE.

DFSMShsm default

If you do not specify the TAPEMIGRATION parameter on any SETSYS command, DFSMShsm does not migrate data sets to ML2 tape volumes unless migration to an ML2 tape volume is indicated by an external-to-DFSMShsm factor. Any tape volume is used. Fast subsequent migration is disabled. This is the equivalent to SETSYS TAPEMIGRATION(NONE(ROUTETOTAPE(ANY)) RECONNECT(NONE)).