[Beowulf] Estimating cluster power consumption

[r reynoldson]

Hi all. I'm trying to track down some threads from
this group that date back to the fall of 2003 (Sept -
Nov). These don't seem to be in the Beowulf mailing
list archive. In particular, I read in Jeff Layton's
"Cluster Environments" article
(http://www.clustermonkey.net//content/view/40/32/)
that some cluster power considerations were discussed
in these threads.

Alternatively, if someone here has some insights and
can spare a few moments, I have a few questions.

First I should say that I just have a little
experimental cluster (5 nodes including master) right
now, but have an opportunity to more than double this
size very cheaply. The compute nodes are a mixture of
366 - 450 Mhz boxes, 128 - 256 Mb ram. Currently they
have hard drives, but I'm seriously considering going
diskless (for the learning experience, amoung other
things). Also, the compute nodes are just boxes (no
monitor, keyboard, or mouse). The master node has an
1800 AMD cpu, 512 ram, and 60 Gb hard drive. I'll be
mainly using the cluster for number crunching
experiments (primality testing, various integer
factorisation implemetations, etc). A typical cluster
run could last anywhere from a day to several weeks
(possibly months?).

My house, which contains my cluster room, is rather
old. Looking at my breaker panel, it looks like my
cluster room shares a 15 amp breaker with an adjoining
room (sad, I know).

Questions
1) About how many of the above mentioned nodes would I
be able to safely run? 
2) Is there any chance of a fire hazzard if the
breaker is overloaded or will the breaker just trip?
3) How does one estimate how many nodes they can
safely run?
4) Would running the cluster diskless help much with
power consumption? What about no CD and floppy drive?
5) How much juice should be flowing to the room to run
a cluster of 16 such nodes?
6) What's the least expensive way of getting more
electricity to the room? I can't do it myself (at
least I think I can't). Which is the more desirable --
increasing the existing breaker amperage (if possible)
or getting a second breaker box (or replacing the
existing box with a bigger and better box)? The house
has copper wiring in the basement, which may affect
the cost (I also live in Canada too, eh!).
7) What are some good references to answer such
questions? I'd even spend money on a book, if it were
recommended highly enough.

Thanks in advance
Rob

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