On Tue, Mar 21, 2006 at 06:58:05AM -0500, Robert G. Brown wrote: Subject: Re: [Beowulf] Cluster newbie, power recommendations > On Mon, 20 Mar 2006, Charlie Peck wrote:
> >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 > Yeah, that looks like it. Kinda cute in its own way. And you don't > "have" to buy stock aluminum or steel and cut and bend it into shelf > trays for the motherboards, BTW -- there was a design somewhere that > mounted the motherboards onto cookie sheets and "racked" them in a > standard cookie-sheet rack, or a rack like the ones they use in > cafeterias. Slide in, slide out. I believe I originated the cookie tray cluster idea, and then later first mentioned it on the list here: http://www.beowulf.org/archive/2005-November/014108.html Unfortunately, I have no website on it, as I was reluctant to write it up until I had an actual finished working cluster to take pictures of, etc. (Which I still don't have - funny how real work and other distractions tend to interrupt one's hobbies like that...) A hugely useful addition to the basic cookie tray idea was Jim Lux's suggestion here: http://www.beowulf.org/archive/2005-November/014088.html http://www.beowulf.org/archive/2005-November/014091.html So far the double sided foam tape seems to work very well! I've tried it on a SMALL scale - 3 motherboards. They run memtest86+ just fine, but I have not yet tried network booting Linux on them with Warewulf and actually using them heavily in a cluster. I exchanged some private emails back and forth with other interested experimenters about that, but I don't think it's been mentioned on the list yet, so here are further details: I purchased a roll of "3M Double Coated Urethane Foam Tape 4004 Off-White, 1 in x 18 yd", here: http://www.hillas.com/Products/3M_Double_Coated_Foam_Tapes/3M_4004_1_X_18.asp Normal motherboard standoffs raise the board 0.25" off the case. This 3M 4004 tape is nominally 0.25" thick, but once mounted it's actually a bit thinner. The foam tape is very firm, you have to push HARD to compress it much, and then it gradually springs back. Thus, the tape alone seems to do a good job keeping the knobs of solder and other stuff on the back of the motherboard away from the aluminum cookie tray, even when you press down hard while inserting memory sticks or PCI cards. This is good, you do NOT need any additional rigid standoffs on the back of the motherboard. Note, I have NOT yet tried removing one of those taped down motherboards... The tape is somewhat expensive, $46.44 + shipping per roll. For each of my microATX motherboards, I used 3 strips about 9" long each, so I should be able to do about 18*3*12 /27 = 24 motherboards from that one roll. For ATX boards I suppose 1 roll would let you do 18 or 19 motherboards. (And you could probably get away with only 2 strips of tape rather than my 3, if you cared.) It's still a bit time consuming to place the tape and mount the boards, but it is EASY. Drilling holes for standoffs both takes longer and is much easier to get wrong. The double-sided tape is certainly convenient, and I plan to try a thinner version for mounting power supplies, hard drives, etc. as well. In addition to the foam tape, 3M's velcro-like "Reclosable Fastener" tape materials (e.g., SJ3540) might also be interesting for mounting motherboards: http://products3.3m.com/catalog/us/en001/manufacturing_industry/engineered_adhesives/node_GSTHK7XYXKbe/root_GST1T4S9TCgv/vroot_WHG0MWH6QPge/gvel_QM7L6GDVFXgl/theme_us_adhesivetape_3_0/command_AbcPageHandler/output_html As far as installing stuff on the cookie trays themselves goes, I mostly talked about that in my post back in November. But here are some additional bits: Figuring out what fits is most conveniently done in person with an actual cookie tray and actual tray rack, as some of the dimensions are sloppy. The tray itself has angled lips, you lose some space on the sides due to the rack rails extending over the edge of each tray, the tray slides side-to-side a bit in the rack, etc. The nice thing is that none of this mounting hardware is too expensive, so just buying it and fooling around isn't much problem. Remember that the tiny fans in 1U power supplies have an annoying high-pitched whine which tends to carry. So if you use 1U supplies, you definitely want the cluster behind some kind of door, NOT sitting right next to your desk. The motherboards I'm using are microATX (9.5" x 9.5"). 2 of those plus 2 1U power supplies will easily fit on 1 cookie tray. 2 ATX motherboards will also definitely fit on a single cookie tray, and should fit even with 2 1U power supplies as well. With any motherboard substantially larger than ATX, you're virtually guaranteed to fit only 1 board per tray at most. Since my microATX boards are 9.5" square, after mounting them flush up against the long front edge of the cookie tray, I have free space about 6.75" deep at the back of the tray, all the way across. A standard 3.5" hard drive is thin enough that if you mount it flush to the cookie try, it will NOT stick up over the 1" tall lip of the tray at all. This means that you can mount it all the way out to the edge of the tray, even underneath where the tray holding rails stick in, saving a bit of space. There ARE 1U power supplies like the SPI FSP250-50PBL that are only 3.25" wide, so I could easily fit two of them side by side in that 6.75" space. However, my Emacs 1U power supplies are 4" wide so I can't do that. To mount 2 supplies, I need to put them tail to tail. That works fine but takes up most of the free space on the tray, I could MAYBE squeeze 1 hard drive flat onto the tray next to the power supplies but definitely not 2. I could mount 2 1U power supplies on top of each other, but that would require a 1 tray every 3 slots spacing. A better idea, if you want disks, is to mount a 3.5" hard drisk on TOP of a 1U power supply - that fits fine with a 1 every 2 slot tray spacing. This is basically free space for disks, as nothing else is going to fit on top of those power supplies. So if I want to, on each tray spaced 1 every 2 slots, I can definitely fit 2 microATX motherboards, 2 of my 4" wide 1U power supplies, and 2 hard drives (1 on top of each power supply). ATX motherboards are about 12" x 9.5" rather than 9.5 x 9.5, so you should still be able to use the exact same arrangment even with ATX rather than microATX boards. And of course, to save even more space, you could experiment with Y-cables to see if you can reliably power 2 motherboards with only 1 power supply, as discussed elsewhere on the Beowulf list. They used to be cheaper, c. $8.50 each for 10+ shipped, rather than the $15.25 they want now, but the power supply Y-cables I found were: CB-Z-Y2020-EXT "ZIPPY Power Cable Splitter: ATX 20 pin to Two ATX 20 pin for ATX Power Supplies" http://www.ateck.com/viewItem.asp?idProduct=453056250 CB-Z-Y2424-SPLITTER "ZIPPY Power Cable Splitter: One EPS12V 24 pin to Two EPS12V 24 pin for ATX EPS12V Power Supplies" http://www.ateck.com/viewItem.asp?idProduct=453056251 -- Andrew Piskorski <[EMAIL PROTECTED]> http://www.piskorski.com/ _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
