[Beowulf] clustering using off the shelf systems in a fish tank full of oil.
eagles051387 at gmail.com
Wed Dec 28 10:04:57 PST 2011
On 12/28/2011 11:17 AM, Lux, Jim (337C) wrote:
> On 12/28/11 7:40 AM, "Prentice Bisbal"<prentice at ias.edu> wrote:
>> There has been a company at the SC conferences for the past 3 years
>> trying to sell exactly that (server cooling by submersion in mineral
>> oil) for the past 3 years.
>> In my opinion it, suffers from a few major problems:
>> 1. It's messy. If you every have to take hardware out of the oil to
>> repair/replace, it's messy. The oil could drip all over, creating safety
>> hazards. And if you need to remove a hardware component from a server,
>> good luck! Now that everything is oily and slippery, there definitely
>> will be a problem with that hard drive once it flies out of your hands,
>> even if there wasn't a problem with it before!
>> 2. The weight of the mineral oil. Despite the density of current 1-U and
>> blade systems, I still think that air makes up a not-significant
>> percentage of volume of the full rack. Fill that space with a liquid
>> like mineral oil, and I'm sure you double, triple, or maybe even
>> quadruple the weight load on your datacenter's raised floor.
> I've worked quite a lot with oil insulation in the high voltage world.
> Prentice's comments (particularly #1) are spot on.
> ALL oil filled equipment that is designed for servicing leaks. ALL.
> Maybe it's just a fine oil film on the outside, maybe it's a puddle on the
> floor, but it all leaks. (Exception.. Things that are welded closed with
> oil inside, but that's not serviceable)
> When you do remove the equipment from the tank, yes, it drips, and it's a
> mess. Slipperyness isn't as big a problem.. You lift the stuff out of
> the tank, and let is sit for a long while while it drips back into the
> tank. Pick a real low viscosity oil (good for other reasons) and it's
> not too bad. The problem is that there is some nook or cranny that retains
> oil because of its orientation or capillary effects, and that oil comes
> oozing/spilling out later.
> Fluorinert is a different story (albeit hideously more expensive than
> oil). It's very low viscosity, has low capillary attraction, etc. and
> will (if chosen properly) evaporate. Equipment that cools by ebullient
> (boiling) Fluorinert cleans up very nicely, because the boiling point is
> chosen to be quite low.
> I'm not sure I'd be plunging a disk drive into oil. Most drive cases I've
> seen have a vent plug. Maybe the holes are small enough so that the oil
> molecules don't make it through, but air does, but temperature cycling is
> going to force oil into the case eventually.
Jim would you plunge an SSD in there? So you wouldnt advise using
mineral oil like the video shows?
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