Using the Tape Retention System (TRS) › TRS Processing Considerations › Free Scratch Chains After a Set Number of Days

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.

When CA TLMS scratches a tape volume it normally retains the information on that tape until it is reused. This information can be used for reference or to unscratch the tape volume. CA TLMS keeps information for each file and volume. For modern high capacity tapes, CA TLMS may be retaining a large number of records containing information on scratch tapes. Some robotic devices use tapes in a circular fashion where a tape is not reused until all of the tapes have been used.

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.