Bill:
Regarding your statement: - A second level VM running as V=V on a VM in BASIC mode will take the vSIE hit as well -
The dilemma here is that we have been running 2nd-level VM systems (and VSE or MVS guests under them) for many years (it's how the company makes money!). Probably most of the VM guests were running V=R or V=F. What approach do we need to take, for the future, to regain the necessary throughput that we lost with the demise of V=R? Based on the documentation I have seen, using LPARs for all (presently) 2nd-level VM machines is probably the only answer. Is that correct?
Also, is the z800 running z/VM5 a bottleneck that warrants a hardware upgrade - probably to the z9 series?
I am going to have to place my head on the block and make a firm statement of direction. I have a preference to retain the special connection my head and my body currently have! :)
Thanks for your input.
David Wakser
InfoCrossing
-----Original Message-----
From: Bill Bitner [mailto:[EMAIL PROTECTED]]
Sent: Monday, July 31, 2006 10:37 PM
To: [email protected]
Subject: Re: Performance under z/VM 5.1
Apologies for missing this thread earlier. Please look at http://www.vm.ibm.com/perf/tips/z890.html
There was been a lot of confusion in this area, and I'm responsible for some of the confusion. To comment on a few of the side threads:
- Do not hold breath for BASIC mode to return. In order to be cost effective in bringing things such as Logical channel sets, LPAR is required. Just one example.
- The 80/20 rule for combating SIE breaks in the multi-level environments is I/O. Trading off memory for I/O is usually the best approach. There are other games one could play, but the return on investment usually doesn't pay off.
- Even the new assists do not all apply to VM on VM on LPAR
- A second level VM running as V=V on a VM in BASIC mode will take the vSIE hit as well.
Bill Bitner - VM Performance Evaluation - IBM Endicott - 607-429-3286
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