[Beowulf] Newbie question.
rsweet at aoes.com
Fri Oct 29 05:18:59 EDT 2004
On Thu, 28 Oct 2004, Currit, Dennis wrote:
> We are thinking of putting up a cluster to run MSC Nastran and have about
> $25,000 budgeted for hardware.
Have you also discussed licensing with MSC? It may have
changed recently, as my experience here is a few months
old, but Distributed Parallel features are licensed differently than the
SMP Parallel features, and are significantly more expensive.
> Is this enough to get get started?
Certainly it is enough to buy a few nodes, but also if you are just
getting started with clustering it may be good to think a couple of times
about the direction you want to go and to analyse the associated costs of
things like additional power consumption, air-conditioning, etc.... If you
already have a sufficient server room infrastructure (racks, power, ac)
then perhaps this isn't much of a consideration.
> Any suggestions as to what I should buy?
We are currently running NASTRAN with success on opteron, though we have
also had good experience with PIV and Athlon MPs. I think the best thing
to do is to try and benchmark your actual jobs on a few different systems
if you can.
> Currently we are running large jobs on
> an older AIX multiprocessor system and smaller jobs on a Xeon 2.8 system, so
> I think even a small cluster should be an improvement.
It depends upon the jobs that you are running. If your jobs do benefit
well from running in SMP on the AIX system, then you may also have good
efficiency with DMP on a cluster. We have had mixed results with our
structural analyses: some had near linear speedups on smallish (<16 cpus)
cluster runs, and others would gain only about 20% for each cpu added.
For many of our NASTRAN runs high speed disk IO is nearly as important as
as the CPU. Find out what your job mix is like, and then spend your money
accordingly (you may want to splash on fast SATA local disks for scratch
space, or on more RAM to use RAM disks for scratch).
Also have the engineers read through the manual regarding the DMP options
because you have to pay a bit more attention to how your jobs are
configured when using distributed parallel.
Ryan Sweet <ryan.sweet at aoes.com>
Advanced Operations and Engineering Services
AOES Group BV http://www.aoes.com
Phone +31(0)71 5795521 Fax +31(0)71572 1277
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