I(ve got a CP mod that allows a Reserve/Release on non-fullpack
volumes.  Created for my customer at a time they had 3 or 4 softwares
that each needed 2 R/R minidisks.  Without the mod, we'd had to devote
8 full packs, each with a few cylinders in use.

The mod is basically simply commenting out the check for fullpack
minidisks, HCPGDS is the module name, 6 lines to comment (another 6
lines were required to avoid R/R being sent to next existing HW for
VDISKs).  This mod didn't require any change since I created it
somewhere in the VM/ESA timeframe.
But, it is left to the sysprog not to place more than 1 minidisk
requiring R/R on a given pack.  Because, the mod is so basic: a
Release requested by a virt machine is let through to the HW, nothing
exists to check if no other minidisk on that volume has an outstanding
Reserve, what would require that the disk should still remain Reserved
for this system on the HW level.

Available on request, alongside a small asm program one can use to
check that R/R is indeed passed to the HW.  Obviously: use on your own
risk.

2009/1/15 Florian Bilek <[email protected]>:
> Dear all,
>
> Thanks a lot for this real quick answers. Have hoped to avoid a
> reconfiguration of the storage subsystem.
>
> Seems there would be some room for future enhancement of this issue ;-)
>
> Best regards,
> Florian
>



-- 
Kris Buelens,
IBM Belgium, VM customer support

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