That works; however, it precludes the sharing of a disk among multiple MVS or VSE guests running under the same CP. If only one user needs access to the disk, then dedicate or attach are sufficient. You do need to insure that the devices shared this way are shared in the RDEV, either through the SYSTEM CONFIG file or via command.
Would making the devices unsupported prevent the command rejects on reserve and release CCWs? Of course, doing that opens another can of worms. Regards, Richard Schuh > -----Original Message----- > From: The IBM z/VM Operating System > [mailto:[EMAIL PROTECTED] On Behalf Of Quay, Jonathan (IHG) > Sent: Thursday, April 10, 2008 12:50 PM > To: IBMVM@LISTSERV.UARK.EDU > Subject: Re: Ten Questions to ask a Prospective z/VM Systems > Programmer > > We used to DEDICATE the packs to the MVS or VSE images > running underneath and share across physical CECs (3090 days). > > -----Original Message----- > From: The IBM z/VM Operating System > [mailto:[EMAIL PROTECTED] On Behalf Of Alan Altmark > Sent: Thursday, April 10, 2008 3:38 PM > To: IBMVM@LISTSERV.UARK.EDU > Subject: Re: Ten Questions to ask a Prospective z/VM Systems > Programmer > > On Thursday, 04/10/2008 at 02:54 EDT, "Quay, Jonathan (IHG)" > <[EMAIL PROTECTED]> wrote: > > To share with other LPARS you need REAL reserve/release, > which I think > > entails coding SHARED in on the RDEV in the system > configuration file. > > 1. The MDISK must be defined as MWV. If you don't do that, > the virtual machine will get a COMMAND REJECT on a RESERVE CCW. > > 2. A successful RESERVE is always enforced on the local VM system. > Always. > > 3. If the MDISK is a fullpack minidisk (DEVNO or 0-END) then > the minidisk is ELIGIBLE for real RESERVE/RELEASE. > > 4. If the volume containing the mdisk is defined as SHARED in > SYSTEM CONFIG or via SET SHARED ON, a virtual R/R will be > enforced locally AND a real R/R will flow to the volume. > > So the only case where a real Reserve/Release is used is MWV > + fullpack > + > SHARED. > > Alan Altmark > z/VM Development > IBM Endicott >
