Reducing the number of partially full tapes

When an ML2 tape that is currently being used as a migration or recycle target is needed as input for a recall or ABACKUP, the requesting function can take the tape away whenever migration or recycle completes processing its current data set. When recall or ABACKUP is finished with such a partial tape, DFSMShsm leaves it available as a migration or recycle target again, regardless of the PARTIALTAPE setting.

During initial selection for an ML2 tape for output from a migration or recycle task, DFSMShsm tries to select the partial tape with the highest percentage of written data. An empty tape is selected only if no partial tapes are available.

There are three related options for the LIST TTOC command:

SELECT(RECALLTAKEAWAY) lists only those ML2 tapes taken away by recall. (If this list is too extensive, you may want to tune your ML2 tape migration criteria.)
SELECT(ASSOCIATED) lists only those ML2 partial tapes that are currently associated with migration or recycle tasks as targets on this host or any other in the HSMplex (two or more hosts running DFSMShsm that share a common MCDS, OCDS, BCDS, and journal).
SELECT(NOTASSOCIATED) lists only those ML2 partial tapes that are not associated with migration or recycle tasks as targets.

The RECYCLE command for ML2 can recycle some of these partial tapes. By using the SETSYS ML2PARTIALSNOTASSOCIATEDGOAL parameter, you can control the tradeoff between having a few under-used ML2 tapes versus the time needed to recycle them. If the number of nonassociated ML2 partial tapes in the HSMplex that is meeting the PERCENTVALID and SELECT criteria for recycle exceeds the number specified by the SETSYS parameter, recycle includes enough partial tapes to reduce the number of partial tapes to the specified number. Recycle selects those tapes to process in the order of least amount of valid data to most amount of valid data.