Return scratch volume chains to the TLMS reuse chain

Document ID : KB000006884
Last Modified Date : 14/02/2018
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Issue:

When a tape is scratched, the volume and dataset chaining records remain intact until one of the volumes is reused. At that time, the volume series is cleared and the chaining records are returned to the chaining free pool for reuse.   Some robotic devices use tapes in a circular fashion where a tape is not reused until all the tape pool has been used. This can cause volume chains to spend more time in the used chain pool when they could be the free-chain pool within CA-TLMS.

Environment:
z/OSTLMS 14.0
Cause:

This could cause a CA TLMS volume chaining shortage.

Resolution:

Free Scratch Chains After a Set Number of Days

You can use a SYSIN control statement to use TRS to free unneeded records from the VMF.

To free records used for unneeded information on scratch tapes, specify the following control card:

FREE-SCRATCH-CHAIN-AFTER DAYS=nnnn

  • nnnn
    Specifies the number of days after a volume is scratched.

Before the scratch chains are freed all of the following conditions must be met:

  • The volume must have been scratched for more than nnnn days.
  • TRS must have processed the volume and moved it to the Data Center.
  • The volume must have a multi-volume or multi-data set chain in the VMF.
  • The DSN must be non-blank.

Notes

  • To prevent excessive overhead, this feature only frees 200 chains per TRS run.
  • This feature does not affect scratch tapes which do not have multi-volume or multi-file chains because no records can be freed.
Additional Information:

TLMS 14.0 Online Manuals

https://docops.ca.com/ca-tlms/14/EN