In my past life, on VM/370 (yes that far back), VM always played nice with our MVT and MVS 3.8 system. VM has the concept of "system owned" volumes. You must specify these in a control file on the IPL volume. Also, VM does not use a z/OS type VTOC at all (well, there is a VOL1 and a 1 track VTOC which says "no space available"). It has its own formatting. The VM system will not try to use any volume itself which does not have a VM directory on it. You must create this using a VM utility. And VM itself, as opposed to a guest under VM, will not touch a volume which does not have this directory on it. IMO, it is more likely that z/OS will trash a z/VM volume than vice versa. I'd strongly suggest keeping the z/VM volumes off line to z/OS. z/OS does not "play nice with others". It is a bit arrogant and thinks it is the only thing in your environment.
And, FWIW, we have run our current z/OS systems under z/VM for the past 5+ years at Sungard. We have never had a problem due to a z/VM malfunction. IOW, you should not have any fears. The only fear would be if you deliberately ATTACHed a z/OS volume to a guest and the guest (such as CMS) were to write on the volume. There is a z/VM list available at mailto:lists...@listserv.uark.edu In the body: subscribe ibmvm Ron MacRae -- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets(r) 9151 Boulevard 26 * N. Richland Hills * TX 76010 (817) 255-3225 phone * john.mck...@healthmarkets.com * www.HealthMarkets.com Confidentiality Notice: This e-mail message may contain confidential or proprietary information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. HealthMarkets(r) is the brand name for products underwritten and issued by the insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake Life Insurance Company(r), Mid-West National Life Insurance Company of TennesseeSM and The MEGA Life and Health Insurance Company.SM > -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:IBM-MAIN@bama.ua.edu] On Behalf Of Ron MacRae > Sent: Wednesday, May 16, 2012 3:04 PM > To: IBM-MAIN@bama.ua.edu > Subject: Co-existance of z/OS and z/VM on same DASD farm > > Hi all, > We are currently an exclusively z/OS site with > multiple LPARs sharing a single IOCDS and DASD farm. We are > about to install z/VM in a new LPAR and I'm worried about > both OSs sharing the same DASD farm. They will not be sharing > at the volume level. > > I've read through the install doc and it all seems fine, you > tell the install process 6 or 9 unit adresses and it goes and > loads stuff onto them and then you IPL. There is no mention > of modifying other volumes, however there are include and > exclude unit address lists that you can specify to define > what z/VM will try to look at, which presumably you can't get > at until after the basic install and IPL. Also z/VM can issue > sense commands to determine what devices are out there. > > The reason I'm worried is that in a previous life, over 30 > years ago, my previous company attempted to do the same > between an VM system and a DOS/VSE system. This was a long > time ago on a real machine in pre LPAR days. > When they brought up VM for the first time it objected to the > VSE VTOCs it found and rewrote them as OS VTOCs and we lost > the whole DASD farm. Management were not best pleased. I > wasn't directly involved at that time so I'm not 100% sure of > my facts here and perhaps the guys who did this did something > wrong, however my worry still remains. > > My question is - Do we have to isolate z/VM from the z/OS > volumes or will z/VM play nice and leave stuff alone? > > I just want to double check that VM will only touch the 6 > volumes it is given at install time. > > Regards, Ron MacRae. > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
