On Thu, Apr 10, 2008 at 8:53 PM, Schuh, Richard <[EMAIL PROTECTED]> wrote:
> 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. Virtual Reserve/Release is needed when you have virtual machines that share a R/W disk with proper protocol. Real reserve/release is necessary when you share between LPARs. The combination of virtual and real reserve release is when you have multiple virtual machines as well as different LPARs (or systems). There is no shortcut for this. The other gotcha is that your mini disk must start at cylinder 0 to make the real reserve/release work. The other interesting thing is that for example RACF does not use reserve/release, but does try it to see whether the disk is shared. Careless configuration may cause it to take a long route where it should not, or may corrupt your database. Rob -- Rob van der Heij Velocity Software GmbH http://velocitysoftware.com/
