Updating MC1 free space information for ML1 volumes after an return code 37 in a multi-host environment

If the selected ML1 volume fails with return code 37 and this is the last try, the failing volume is LSPACed and the MC1 free space is updated if the volume is active. The remaining ML1 volumes are LSPACed. The MC1 is updated for those volumes in which the MVT free space is below the number of tracks specified in the MCVT_L1FRESP field and the free space has changed by more then the number of tracks specified in the MCVT_L1SD field.

Patch the MCVT_L1FRESP higher or lower depending on the free space level at which you want to trigger an immediate update of the MC1 for active volumes.

Guideline: Set the MCVT_L1FRESP field to a value at least two times the size of a backup VTOC copy data set. This helps prevent out-of-space conditions during volume backup, volume dump and FREEVOL. For example:

PATCH .MCVT.+560 X'00001388'

Note: MCVT_L1FRESP is initialized to 4500 tracks at startup.

If the same volume continues to be selected when there are other volumes with more free space, patch MCVT_L1SD lower. For example:

PATCH .MCVT.+564 X'000000C8'

Note: Note: MCVT_L1SD is initialized to 500 tracks at startup.