On Mar 20, 2006, at 6:50 PM, Robert G. Brown wrote:
On Sun, 19 Mar 2006, Eric Geater at Home wrote:
Howdy, everyone!
Maybe this is a question better suited for hardware heads, but I've
become
Beowulf curious, and am interested in learning a hardware question.
I have access to a bunch of old ATX computers. The most likely common
processor will no doubt be Pentium II 400, with hard drive space
around 10gb
...
This is a power-saving concept... if I could run 16 mobo's on 8 (or
even 6)
power supplies, it might be more beneficial to my health and
well-being when
the electric bill comes in.
Sigh. If you do the math, you are better off buying a single AMD64
than
using the whole cluster for "work", especially as far as power is
concerned. 16 mobos is likely close to 1600 watts -- almost certainly
over 1000 watts even if you use larger/collective power supplies.
Compare that to the 100-200 watts for a single AMD64, and you're
looking
at an ~$800/year difference in cost paying for the electricity and
cooling alone (at an estimated $1/watt/year, which is a bit high
depending on where you live but probably not even a factor of two
high).
I think clusters like the one Eric wants to build have /significant/
educational value, both in the building and the use. How else does one
learn to do parallel/distributed programming if not on a cluster, even
a "toy" one? Sure the single AMD64 will be more powerful but it won't
provide an opportunity to learn about message passing, speedup,
efficiency, problem decomposition, etc.
not the work. If this describes you, then I'd suggest not worrying too
much about the power saving right away -- somebody on this list (I can
think of a couple of folks offhand:-) will likely suggest SOME ways of
doing collective power, and there used to be a really nice shelved
cluster on the web that used a single beefy power supply and special
connectors per shelf of something like 4 motherboards. Google harder
--
hopefully it is still there (or check the list archives to see if you
can find a reference, this was a year plus ago). When they do or you
There are a couple of issues when ganging multiple power supplies, most
having to do with the lines in the ATX standard where the board sends a
signal back to the power supply. I believe the site that RGB is
referring to is http://joule.bu.edu/~hazen/LinuxCluster. If this isn't
enough get in touch, we have worked through these same problems for our
portable clusters, see http://cs.earlham.edu/little-fe
charlie
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