Patching to allow building of a dummy MCD record for large data sets whose estimated compacted size exceeds the 64 KB track DASD limit

Issue the following patch if you want DFSMShsm to build a dummy MCD record for a large data set when the initial migration attempt fails with an ABENDSB37 because the data set did not compact well:

PATCH .MCVT.+595 BITS(1.......)

The dummy MCD record is used to determine if subsequent attempts to migrate the data set should be allowed. If the estimated compacted size, based on the current size and saved compaction history, exceeds the 64 KB track limit, the migration will fail with the following messages: ARC0734I RC=8, REASON=10, or with ARC1001I RC=0008, REAS=0010 and ARC1208I. The RC0008 and REAS0010 indicate that the DFSMShsm-owned copy of the data set to be migrated is estimated to be greater than 64K tracks. The data set is eventually migrated to ML2 tape when eligible.

Note: The dummy MCD record is built for data sets with an original size greater than 64K tracks that don't compact well when migrating. It is also built for data sets whose size is less than 64K tracks but may grow beyond the 64 KB track DASD limit on the migration volume due to reblocking and control data.