You don't. Virtual Reserve/Release emulates the real reserve and release CCWs when you have two guests in the same LPAR sharing an O/S or VSE disk. Real R/R would be of no help in that instance because it applies at the control unit level and reserves the device to an LPAR or, if running in basic mode on a pre z9 system, a physical machine. Any access from that same LPAR or machine is allowed. That is why Virtual R/R is needed when there are multiple guests sharing the same disk.
Regards, Richard Schuh > -----Original Message----- > From: The IBM z/VM Operating System > [mailto:[EMAIL PROTECTED] On Behalf Of McKown, John > Sent: Thursday, April 10, 2008 11:44 AM > To: IBMVM@LISTSERV.UARK.EDU > Subject: Re: Ten Questions to ask a Prospective z/VM Systems > Programmer > > > -----Original Message----- > > From: The IBM z/VM Operating System > > [mailto:[EMAIL PROTECTED] On Behalf Of Schuh, Richard > > Sent: Thursday, April 10, 2008 1:30 PM > > To: IBMVM@LISTSERV.UARK.EDU > > Subject: Re: Ten Questions to ask a Prospective z/VM Systems > > Programmer > > > > > > If you share with a user outside your own LPAR, you need real > > Reserve/Release, not virtual. The virtual is for when you have > > multiple guests running in the same LPAR, under the same > CP, who need > > the Reserve/release. Virtual reserve/Release will do nothing to > > prevent clashes with other LPARs. > > > > > > Regards, > > Richard Schuh > IIRC, virtual reserve / release plus a full-volume mdisk is > needed to share with other systems on other LPARs > successfully. I.e. the virtual reserve / release, in that > case, actually does a reserve to the volume in question. > > -- > John McKown > Senior Systems Programmer > HealthMarkets > Keeping the Promise of Affordable Coverage Administrative > Services Group Information Technology > > The information contained in this e-mail message may be > privileged and/or confidential. It is for intended > addressee(s) only. If you are not the intended recipient, > you are hereby notified that any disclosure, reproduction, > distribution or other use of this communication is strictly > prohibited and could, in certain circumstances, be a criminal > offense. If you have received this e-mail in error, please > notify the sender by reply and delete this message without > copying or disclosing it. >
