[Beowulf] Q: Cooling units? Raised floors? General machine room stuff..

[Brian Dobbins]

Hi guys,

  I've recently put together a plan for a machine room in one of our lab
spaces, but I'm not very knowledgeable about cooling (or infrastructure
in general!), and would love to hear some thoughts on what the experts
here think.

  At the moment, a high-end power estimate is approx. 14.5kW for the
systems we'll be running in the near future, and using Dr. Rob Brown's
figures from his (excellent) writeup on Beowulf Infrastructure
(http://www.linux-mag.com/2003-06/infrastructure_01.html), I'm
estimating about 4.2 tons of AC needed.

  So here's the first of many questions - given the fact that we expect
to expand our resources in the future, do we go with a much larger AC
now?  Or is it possible/useful to simply add a second one later?  And
are there any particular AC vendors people tend to recommend?

  Secondly, given this is a rather small machine room (aiming for a max
capacity of 5 42U racks), what advantage would be found in going with a
raised floor?  And does anyone have any cost estimates on raised floors
for rooms on the order of, say, 15' by 15'?

  Finally, what other suggestions do people have for equipment needed? 
On my list we've got the UPS, the AC, thermal sensors and killswitches,
APC Masterswitch units, power lines, network lines, web/video camera and
an alarm.  Anything else people find useful?

  Thanks very much,
  - Brian

Brian Dobbins
Yale Mechanical Engineering