My understanding is that Appendix A of SG24-4987 ("Linux for S/390") gives,
to my eyes, a good overview of how an S/390 (and now zSeries) differs from
an Intel. Having a huge cluster of Intel CPUs doesn't really give you what
a mainframe can provide.
Look, I don't know where the zSeries stands in number crunching (did
[EMAIL PROTECTED] ever build a VM/CMS version?) but the mainframe is optimized for
single-thread performance. A cluster does NOT give you single-thread
performance... and that's ignoring how you dispatch the workload in a
closely coupled SMP... especially since CPU power of a system doesn't
scale at 1:1 with additional CPUs unless heroic measures are taken to
minimize competition for main memory (I recall some of the tricks used in
the ol' UNIVAC 1100/80 to get around that). The main thrust of the zSeries
is to deal with huge quantities of data which, really, not many other
systems can cope with as neatly.
The real strength of a mainframe is the "take no prisoners" attitude
towards compromising H/W reliability _just_ for throughput-- though I/O
bandwidth and connectivity is _another_ historical advantage of mainframes
(I've no idea how the equation is now stacked given the new "DASD Farms"
like the Shark).
Now if only I had a real mainframe to play with ... though some of the new
pSeries boxes I do have ain't looking too shabby, but then I'm a pSeries
kinda guy.
--------------------
John R. Campbell, Speaker to Machines (GNUrd) {813-356|697}-5322
Adsumo ergo raptus sum
MacOS X: Because making Unix user-friendly was easier than debugging
Windows.
Red Hat Certified Engineer (#803004680310286)
IBM Certified: IBM AIX 4.3 System Administration, System Support
----- Forwarded by John Campbell/Tampa/IBM on 10/12/2004 10:54 AM -----
"Post, Mark K"
<[EMAIL PROTECTED] To: [EMAIL PROTECTED]
m> cc:
Sent by: Linux on Subject: Re: [LINUX-390] Linux
Questions
390 Port
<[EMAIL PROTECTED]
IST.EDU>
10/11/2004 03:30
PM
Please respond to
Linux on 390 Port
I don't know that there's anything specifically comparing Linux on z/VM
versus VMWare. VMWare is one of the virtualization tools IBM is
recommending for their xSeries customers, so it has some merit to it.
Perhaps your local zSeries sales rep will have some thoughts on why VMWare
on Intel is not as good a choice as z/VM on zSeries hardware. :)
>From my perspective, VMWare is not nearly as mature a technology as z/VM.
It doesn't have anywhere near the system management and Linux-enabling
features that z/VM does. The Intel platform is not nearly as rock solid as
zSeries. If you price a full-blown Intel system with redundant everything,
etc., etc., you're getting up into the 10's of thousands of dollars, even
up
to $50K. It only takes a few of those to add up to one mainframe. They'll
knock your socks off on CPU-intensive workloads, of course, but if you have
a lot of mainframe-resident data that needs to be accessed, having a Linux
system on the same box and using HiperSockets is a nice setup for a number
of reasons.
Take a browse through the news articles and press releases at
http://linuxvm.org/Info/l390link.html to get a feel for why other people
have made the move, and see if any of it applies to your circumstances.
Mark Post
-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Seader, Cameron
Sent: Monday, October 11, 2004 10:50 AM
To: [EMAIL PROTECTED]
Subject: Linux Questions
Greetings,
Having troubles with promotion of Linux for zSeries in corporate
environment. I'm Hopeing someone here can point me to some good documents
on
the strengths against an intel platform running VMWARE. There have been
Questions come up about performance, Oracle, How many guests can we put out
there and what kind of performance loss per guest do we get or can we
expect? Just want to justify in spending a quarter of a million on the
hardware and be able to get what we need out of it. Does anyone know of
some
good docs pointing to these answered questions.
-Cameron
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