On Monday, 04/05/2010 at 01:19 EDT, Brian Nielsen <bniel...@sco.idaho.gov> wrote: > Does Standalone DDR (directly in an LPAR, not under z/VM) do a hardware > assign & release for the 3590 tape drive addresses it uses?
Yes. When running standalone, drives are assigned on first use and unassigned at EOJ. > I'm thinking ahead to an upcoming DR exercise in which while I'm running > DDR native in one LPAR some z/OS images are being IPL'd in other LPARs > that also have access to the same tape drive ranges. I know z/OS does the > hardware assign when it varies the drive online, and I'm wondering if that > will negatively impact Standalone DDR's access to the tape drive it is > using. Once I'm far enough along that I can run DDR under z/VM I know it > won't be an issue because z/VM will do the assign when the drive is > attached to a virtual machine. Yes, it will be an impact; MVS has to unassign the drives that DDR wants to use, if he has already assigned them (first one up wins). If you have z/VM up and a good quality tape management product running, it can talk to z/OS and get the drives unassigned, depending on what tape management software you have running on z/OS. For SA DDR, you will have to manually take them offline from MVS before you run DDR. Alan Altmark z/VM Development IBM Endicott
