On Tuesday, 03/15/2011 at 06:59 EDT, Kris Buelens <kris.buel...@gmail.com> wrote: > I've got a customer that performed a DRP test last weekend. The disks at the > DRP site are EMC, and he uses Snapshot plus PAV. > > The customer told me that in Jan 2010, EMC told him to define most disks as > unsupported, like this: > > RDEV 5126-513B TY UNSUP DEVCL DASD DPS Y RESERVE_REL Y > > But, at IPL, I already get lost of these: > HCPIIO6861I Device 5186 cannot be varied online because it is an alias > Parallel Access Volume for which the base could not be located. > I found out that these messages appear for disks whose base address is defined > as unsupported. > > That's not that bad, but in addition, the customer want to define quite some > disks as MDISK DEVNO so they can be shared between the z/OS guests. Like this > MDISK 5809 3390 DEVNO 5809 MWV > This makes we get lots of > HCPLNM117E Userid xxxxxx not linked; volid conflict > We get these messages for the disks that are defined defined as Unsupported. > > I understand perfectly well that it is impossible to define an MDISK on an > unsupported device. But, the customer replied me that EMC told them to work > this way. > > My question: is it really required to define the disks that are candidate as > Snapshot target as unsupported. Or is there another reason to do it? > (my customer doesn't remember exactly why, but he told me that the EMC guys > giving him that advice didn't seem to know much about z/VM)
I did some more research. z/VM was updated some time ago to deal with the unusual mix of 3880/3990/2107/2105 controller functionality on EMC devices. But EMC TimeFinder/Snap, remains proprietary EMC technology that z/VM does not support for minidisks. My only recommendation for sharing is to use the technique described on p. 85 of the IOCP book (-08 level): When you are running VM with guest operating systems, you can use multiple CNTLUNIT statements for a single physical control unit in certain environments to effectively dedicate the same physical devices to more than one guest. This technique involves potential path-grouping considerations that create operational complications. Ensure you have determined possible consequences and that you use caution if employing this technique. If EMC told the customer that they can create MDISKs (DEVNO or otherwise) on TYPE UNSUPPORTED dasd, they were wrong. BTW, "Snapshot" is a function in the IBM RAMAC Virtual Array (RVA) Alan Altmark z/VM and Linux on System z Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott
