I have run into a lot of folks, but we bought the first zSeries machine that I
know configured to run only z/VM and Linux. May have something to do with
longevity... :)
I'd recommend that you look twice at loading things like print servers and etc.
on a zSeries unless you are basically swimming in free MIPS. A lot of Linux
stuff is written with very little, if any, consideration for efficiency. Take
Tivoli Storage Manager for instance... it can easily bring a z800 IFL to it's
knees in seconds, and even with a dedicated channel (configured as Fibre
Channel Protocol of course) it can not seem to drive a 1120 tape anywhere near
normal speed. Most of that is because it swamps the CPU with database updates.
(*sigh*)
There *are* some things that Intel / AMD processors can do better - for
example, I suggest you talk to RSA (Rochester Software Associates) about
printing. We have managed to come up with a total replacement for InfoPrint
that works from zLinux, i5OS, and Winders without much trouble, and hosting the
print server on an Intel Blade means we have lots of speed and redundancy.
On the other hand, there is not doubt at all that a well designed *efficient*
application under zLinux can and does directly complete with just about any
other platform in the world, including z/OS. Admittedly, we write most of
appliations in HLASM under zLinux, so we are less likely to include "cruft" in
a program, but we still make intensive use of the stdlib and all sorts of C
calls where appropriate. For example, we use the stdlib for I/O. We did layer a
homebuilt ISAM/VSAM like filesystem over that, but that was driven by (1) No
VSAM under zLinux and (2) even DB/2 is slower than what we wanted. We looked at
using some of the COBOL compilers, which were *great*, but we did not like
paying a per user cost.
On the other hand, tasks that are pretty efficient CPU wise and hogs I/O wise
run fantastic on the zSeries machine - stuff like basic print management (no
overlays, no data merges, that kind of stuff), web servering, FTP servers, just
about any kind of network server including NFS, user interactive tasks, etc.
It's a slightly different world, and you can take advantage of 'Open Systems'
in ways that are both innovative and sometimes amazing.
-Paul
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Does anyone happen to know a ballpark figure of how many companies are
using zSeries Linux??
My reason for asking is I am working on trying to convince the management
here that we could
save tons of money by consolidating a lot of the easier workloads (ie-
print servers) to zSeries
Linux. One of the things I get back is "no one is doing it", although I
have to think there is a lot
of it being used, especially with todays economy as it is.
I think IBM has not done a very good job of promoting zSeries Linux,
although from a marketing
standpoint they undoubtedly make more money with a room full of p-boxes
than one or two z-boxes
running the same workload.
Thanks,
Paul Adrian.
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