Jim Lux
-----Original Message----- From: Lux, Jim (337C) Sent: Friday, September 28, 2012 2:40 PM To: Lux, Jim (337C) Subject: RE: [Beowulf] let's standardize liquid cooling And here we go with the low budget approach to large diameter fan cooling of many nodes: Eschew conventional chassis. Use an $8 18x26" aluminum sheet pan: http://www.foodservicewarehouse.com/thunder-group/alsp1826m/p548194.aspx Attaching the mother board and other equipment to the pan with double stick foam tape: http://www.3m.com/product/information/VHB-Acrylic-Foam-Tape.html (most expensive single component is the tape) Supported by 20 tier rolling racks: http://www.foodservicewarehouse.com/channel-mfg/401akd/p349120.aspx (about $100) With an array of 3 each 20" box fans on either side of the rack as needed. (or front and back..) (about $16 each.. and heavily discounted this time of year) http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?productId=100405665&storeId=10051&langId=-1&catalogId=10053&ci_sku=100405665&ci_kw={keyword}&kwd={keyword}&cm_mmc=shopping-_-googleads-_-pla-_-100405665&ci_gpa=pla#.UGYXiFHvy4g Note they claim 2500 CFM flow (per fan). Those little 25-35 mm fans push maybe 1 CFM. Stack 40 U high, and 10 across, and you're still only at 400 CFM. Maybe they don't look as pretty as 19" racks, but face it, with a 19" rack and conventional sheet metal chassis, you're buying LOT of metal that you don't really need in this application. Once the node is in the cabinet, why does it need a box around it? You could make a very pretty looking version of my bakery rack scheme. Rolled edge pans with prepunched holes for the motherboard on standoffs, etc. Solid sides and doors with integrated fans. A lot of the weight in a conventional rack is there for structural reasons.. to hold up the sheetmetal boxes around the motherboards. The mobos themselves weigh very little, after all. Jim Lux -----Original Message----- From: beowulf-boun...@beowulf.org [mailto:beowulf-boun...@beowulf.org] On Behalf Of Lux, Jim (337C) Sent: Friday, September 28, 2012 2:26 PM To: Bill Broadley; beowulf@beowulf.org Subject: Re: [Beowulf] let's standardize liquid cooling An interesting idea.. BUT.. you might need some sort of "bench test" fixture.. thermally driven convection might work. And I think you'd have mfrs worried about people filling a rack full of fanless nodes and then not turning on the fans. Or the power failing to the fans, or, opening both doors. I suppose some sort of overtemperature cutout would solve this: the mobo would just shut down if it got too hot. Whatever happened to a Beowulf made of tower cases piled on brick and board book cases? Or this incredibly adaptable scheme: http://climate.ornl.gov/~forrest/linux-magazine-1999/ note the easy reference information inscribed on each node in this novel heterogenous cluster. It's all part of addressing: "Management of such a large, heterogeneous cluster poses many challenges." Jim Lux -----Original Message----- From: beowulf-boun...@beowulf.org [mailto:beowulf-boun...@beowulf.org] On Behalf Of Bill Broadley Sent: Friday, September 28, 2012 2:15 PM To: beowulf@beowulf.org Subject: Re: [Beowulf] let's standardize liquid cooling Sounds expensive, complicated, and challenging. How about a MUCH simpler proposal: eliminate fans from compute nodes. Nodes should: * assume good front to back airflow Racks would: * have large fans front AND back that run at relatively low rpm, and relatively quiet. * If front or rear door open the other door would ramp up fans (and noise) to compensate. My measurements of 1U nodes have shown a significant fraction of the power budget goes to fans! Fans that fit in 1U (even 2U) nodes seem to generate more noise, heat, and vibration than airflow. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
