Alain,

At the risk of misinterpreting what you're asking, I have to caution you
that because you CAN share tape drives between MVS systems with the
"multiuser" option, it doesn't mean you SHOULD (at least, using native
facilities).

HELP for the CP ATTACH MULTIUSER option says "The MULTIUSER function is
intended for guest operating systems that manage their own assignment of
tape drives".  MVS does not, by default, manage its own tape drive
assignments.  There may be others but the only facilities I'm aware of
capable of tape sharing are CA's Multi-Image Manager (as described by CA's
own Steve Imler) and MVS' native Automatic Tape Switching (via either
IEFAUTOS or ATS STAR features) and I'm not sure if that works in a
MVS-under-VM environment (and it certainly doesn't work with a CMS workload
included).

Failure to use one of these factilities (or some other equivalent which I'm
not aware of, including home-grown facilities) in conjunction with
MULTIUSER could result in ASSIGN errors (IOS000I ..ASN, as I recall) or
possibly (I doubt MVS will allow this to happen but ...) data corruption.

Be careful.

Dennis Schaffer
Mutual of Omaha


"The IBM z/VM Operating System" <[email protected]> wrote on
03/10/2007 02:28:21 PM:

> I read a similar discussion on the mailing list about assign.
>
> We don't have any tools to share tapes between 1 VM & 20 MVS.
> Something has been developped in the past which is not really up-to-date.

> We remarked it needs too much CPU to do its work.
>
>
> I project to use our VM to be THE platform to share tape drives between
> lpars in a normal prod or when we do our disaster recovery tests
> (MVS are lvl2).
> We only have ATL robots. I just tested one thing that could give other
ideas
> to investigate.
> I have attached a drive with the multiuser option. In parallel it was
used
> by a MVS. Then I tested the dfsmsrm q dev xxx (assign cmd and I was
> surprised to get the volser that was mounted in MVS. If dfsmsrm is able
to
> send back this info, can't it be able to send back the part number or the
> MVS partname too ? That could be great.
> And (What VM diag D0 would say if a tape is mounted in a MVS ?)
>
> Alain Benveniste
>
>
>


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