I'm not even sure how they would wind up on a comparison, but roughly,
if you need high I/O or transactional capabilty -- use z/VM.
If you need a whale of a lot of CPU processing, use Intel.
On Nov 2, 2008, at 9:34 AM, Barton Robinson wrote:
Exactly, but the issue is to explain this to peter principal IT
managers.
Paul Raulerson wrote:
I am very confused indeed by this whole conversation -VMWARE and z/
VM solve different solutions. And they are both extraordinarily
good at what they do.
Just at the 10,000 foot level, VMWARE is designed to virtualize PC
hardware and z/VM virtualizes mainframe hardware. Dismissing this
as just "two different hardware platforms" is rather disingenuous,
though admittedly, it is a "true" statement. Then again, a
nuclear powered aircraft carrier and diesel powered megaton oil
tanker are both ships - just "two different hardware platforms."
They hardly operate in the same realms though.
Where everything starts to get different is the underlying
hardware. And at that level, it gets very VERY different indeed.
In some ways, VMWARE is more like an LPAR than a VM guest
instance, but that difference is driven more by the hardware
capabilities than by the design.
-Paul
On Nov 1, 2008, at 6:34 PM, Barton Robinson wrote:
One thing that really bothers me about VMWARE. When I ask about
performance to the people that measure, they tell me the VMWARE
contract specifically states they are not allowed to talk about
it's performance. A vendor that won't let people talk about
performance must be very afraid details will be made public and
don't really need to invest in improving it's performance. Since
we can not provide facts to confuse management, it comes down to
religion or companies providing their own facts.
A professor from I think Stutgaart presented last year at the GSE/
IBM meeting pretty convincingly that VMWARE was about 20 years
behind z/VM in almost any "fair" technological aspect you wish to
evaluate. And I think he was wrong - I don't see sharing of
resources in VMWARE even what z/VM had 20 years ago. VMWARE is
much more like LPAR, so any argument you can use for z/VM vs LPAR
works as well.
I believe VMWARE is great for desktops where users may want to
run applications that only run on different versions of windows
or Linux. Now there is a company in California that is even
virtualizing the desktops, give end users a small appliance,
keyboard and monitor, and the software runs on a "virtualized
PC", where all software runs on the central "virtualized PC" that
then supports multiple users. They save a lot of money by only
having one copy of MS Office to support multiple end users.
(Does this sound like 3270 and mainframes to anyone else?)
Alan Ackerman wrote:
Another question from the same architecture person. What is the
value add
ed by z/VM over VMWARE for a Linux workload? (That's my wording,
not his.)
As usual, I don't know anything about what VMWARE can or cannot
do. I'm s
ure it can run fewer guests than VM, but not how many. VM has
shared DASD and DCSSes and NSSes
, but most Linux people don't see the value of those things --
disks are cheap and come wi
th the PC, memory is cheap, etc. VM has automation capabilities,
but Linux has those too, and IBM sells all those Tivoli
products to tie them together, report performance, provide high
availabil
ity, etc. I think the advantage on the mainframe is economy of
scale. But how do yo
u measure that?
At present, you can save money on software and peripherals
enough to cost
-justify the mainframe. Reduced people costs are hard to
quantify and scare the heck o
ut of the midrange folks.
But I wonder how long those software prices will last? Red Hat
charges $1
8,000 per IFL for 7x24 support. (I found that on a web site, and
I asked our Red Hat representat
ive to make sure.) I couldn't find any prices on Novel SuSEs web
site. We have other software with higher prices per engine for
the mainframe. He specifically mentioned the ability to pick up
a Linux guest running un
der VMWARE and moving it to another box running VMWARE. So far
VM cannot do that. Ideas on what value z/VM adds would be
appreciated!
Alan Ackerman
Alan (dot) Ackerman (at) Bank of America (dot) com
