On Tue, 28 Feb 2006, Don R. Baker wrote:
for 8 years, but consider myself to still be a beginner. I have a room with 4, 15 amp circuits and a 20 000 btu air conditioning unit installed that I can use for the next 2 years, but after that I may need to find another home for the system.
Let's see. 20KBTU is a bit more than 1.5 tons of AC, call it the ability to remove 5800 Watts total. 4 x 15 x 120 is is 7200 Watts peak, or about 5000 Watts RMS. In my opinion this is going to leave you a bit light on AC if you run the circuits fully loaded, and don't forget warm bodies (60 W) and built in light bulbs etc. on other circuits (maybe several hundred W more). You have to not only remove the heat as fast as it comes in but get ahead some, correct for heat that infiltrates through the walls, and get the room temperature down below 20C (68 F) if at all possible. 15-16C is more like it -- cold enough to just be uncomfortable. If you limit what you run per circuit to roughly 1000 Watts, that is 4000 watts and gives you a bit of margin. Or get a bigger AC -- a 2 ton AC is still pretty cheap and would probably manage fully loaded circuits. Just a thought.
My dilemma is that for my budget I can buy one of the following solutions: Solution #1 A custom built "personal cluster" with 8 dual core processors either Xeons or Opterons (16 cores and 16 GB of memory) with all the software installed, read to go. Solution #2 I can buy 16 workstations, each with Dual Core Athlon X64 4400+ processors (32 cores and 32 GB of memory) upon which I will probably install either Warewulf or Oscar. Solution #3 I can buy 32 HP or Dell "mass market" desktops running dual core chips (64 cores and 64 GB memory) upon which I will probably install either Warewulf or Oscar. (Note that I read the discussion this past November on "cheap PCs this christmas") Obviously, I get more computing power in the last two solutions, but at what cost in terms of time and upkeep? Once the system is up and running I can dedicate about 5 hours per week, and probably no more, and CAD$ ~500 per year for maintenance.
I personally would reject #3 out of hand, unless you buy three year onsite service contracts on the Dells (spending nodes as required). Dell doesn't do Opterons, I don't think, as well. HPs ditto. Solutions #1 or #2 are both reasonable, although I'm not sure where your numbers are coming from. It might be more helpful if you gave us your budget and your software constraints (e.g. how much memory per CPU or core do you need). I'm assuming embarrassingly parallel MC (which is what I do) so the network is basically irrelevant.
Do any of you have some sage advice? Have any of you used a "personal cluster"? Any thoughts you may have will be very much appreciated. Thank you all for your time.
Sure, a bunch of us (myself included) have personal clusters, although yours is going to be mine -- I never have more than about 10 nodes because at that point my house starts to melt in the summertime (and the nodes start to cost roughly $1000/year just to run). Remember, power costs ballpark of $1/watt/year to heat AND remove the heat (within a factor of two) so if you DO fill your room to capacity with 4000 watts running 24x7, plan to spend around $4000/year just to run it and keep it cool.
Wishing you the best from a cool Montreal,
Although there is that -- I suppose in the wintertime you could just open a window and snow-cool it... but that at most knocks it down to $3000, because most of the money is for the power, not the cooling:-).
From this point of view getting fewer, faster nodes (e.g. 8 dual-dual
core processor from e.g. Penguin or ASL (32 processor cores) is likely to be a net savings in power, in money PAYING for power, high quality nodes are less likely to break, and less of your time doing both soft and hard maintenance. I'd really try to keep your system count down for home clusters as they can eat enough time and money to destroy personal relationships with loved ones... They don't have to be preinstalled with linux, though. Oh, they may BE preinstalled (often with SuSE) but I'd advise reinstalling Centos or FC (see archives for pros and cons of choice). That way you get an indefinite free update stream and full yum-ability. SuSE does yum (thanks to Joe Landman of this list, who might ALSO sell you prebuilt nodes) but it ain't necessarily pretty... rgb
Don
-- Robert G. Brown http://www.phy.duke.edu/~rgb/ Duke University Dept. of Physics, Box 90305 Durham, N.C. 27708-0305 Phone: 1-919-660-2567 Fax: 919-660-2525 email:[EMAIL PROTECTED] _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
