The historic reason for not running VM under VM (for production) was that you lost the hardware assists. But the hardware assists are gone anyway.
Are you talking about: LPAR > z/VM > z/VM > VSE? Sure, it is doable. And you can still have good (not great) performance. As long as you have sufficent CPU, and memory. Is this a long term thing? Or just a short term, conversion, type of thing? I've done some 30+ VM installations/conversions. Really, there isn't much to it. The last major hurdle I've hit, was going to VM Version 2. It hit some CMS based applications fairly hard. Other than that, VM conversions have been rather boring. Is this a service bureau kind of thing? Where one client want to be insulated from all other clients? That is a reason for VM under VM. But then it leads to the question, why not LPAR? We no longer have BASIC mode. Do they need to cycle their VM or major componets (tcpip, VTAM, SFS, RSCS, etc) that might effect others? That is a reason for their own VM. It is easier to have their own VM then to duplicate all services that they need to cause outages for. On a modern box, the only major thing that can't be shared between LPARs is bus and tag channels. But if they don't have something "unique" in their VM system, they will be happer to run their VSE second level instead of third level. Tom Duerbusch THD Consulting >>> [EMAIL PROTECTED] 3/28/2006 11:53 AM >>> We are consolidating two data centers. Both data centers run ZVM and VSE/ESA. I happen to be at the "home" data center with the hardware and the host zvm system. The data center being relocated is keeping its network infrastructure, its operator staff, a few tape drives, and its users where they sit today. The data center being located wants its own ZVM under ZVM system. Technically I don't agree. On the other hand, maybe it' not a technical issue. If it's not a technical issue, what business reasons exist to support running a ZVM under ZVM environment? I'm sure there are others who have faced this dilemma in the past. How did you resolve it? I'd like to hear technical reasons why it's a bad idea to run ZVM under ZVM in production or why it's a good idea. Business reasons pro and con are welcome as well. The facts need to speak for themselves, not emotions. Any comments are welcome. Regards, _______________________ Jim Hughes "Impossible is just an opinion."
