________________________________
From: [email protected] [mailto:[email protected]]
On Behalf Of arjuna
Sent: Thursday, December 11, 2008 2:05 AM
To: [email protected]
Subject: Re: [Beowulf] Newbie Question: Racks versus boxes and good
rack solutions for commodity hardware
I am in NewDelhi India. However I would prefer to put the cluster
together myself, because
1) I am a good python programmer and like programming and playing with
computers
2) I will be using the cluster for animation (art + computers) and may
have to bend it and tinker with it...therefore it makes sense for me to know it
inside out.
3) If I set it up then I can grow it, and i envision it growing,
outsourcing the whole thing would be expensive
4) I have been using linux for several years and am comfortable in the
environment
5) I have a bunch of old computers lying about which are not so old and
run basic versions of linux fast.
All decent reasons to put together a cluster.
> What is 1u?
Standard rack mount systems (with 19" wide RETMA/EIA panels) have certain
vertical heights for each component (as well as standard hole patterns). 1 U =
1 Unit = 1 7/8" (4U = 7", 2U= 3.5")
As a practical matter, 1 U high systems are quite tight inside, and tough to
cool, because the fans can only be an inch or so high (maybe 40mm) and to move
any amount of air, they have to spin fast. Fast small fan = low efficiency,
lots of noise..
>What is a blade system?
Where there's a "card cage" into which one slides cards (or "blades") which
are a whole PC. They all share a common power supply and they're denser
because you don't have extra sheetmetal between PCs.
OTOH, denser means more heat in a small volume, which aggravates the cooling
problem.
Why "blades".. -> it sounds cooler (no, really... It's because of marketing.
Cards in a card cage is so 1950s.. Why, PDP-8s and IBM 1401s use cards in a
card cage..)
>I would be putting it in a room with air conditioning.
There's "air conditioning" and "AIR CONDITIONING".. Throw a few kilowatts worth
of computers in a room, and you'll find out which one you have.
>At this time I am trying to figure out the racks. Am meeting the hardware guy
>on Saturday and we were thinking of opening up the PCS i have lying around and
>taking measurements of how the mother boards fit into the cases,with the
>intention of creating a rack from scratch. Any ideas of what goes into a good
>rack in terms of size and matieral (assuming it has to be insulated)
My favorite "field expedient" scheme is to use half or full size aluminum
baking sheets with raised edges (aka jelly roll pans or sheet pans) and double
stick foam tape. You can slide them into a standard baker's rack. All readily
available or improvised, although I'd look for the real rack (they're cheap and
sturdy). The pans can just be sheets of aluminum sheared to size, if you like.
Search the archives of the list for some website addresses of kitchen supply
places where you can see a picture of this kind of thing. There is CERTAINLY
some local source where you live for this stuff (ask at any commercial kitchen
or bakery)
> Also again, what might be some upto date books on the subject and any
> experiences regarding the actual creation of the rack and the physical
> hardware.
Catalogs are your friend, as far as packaging goes.
>I am starting with 3 nodes to be expanded to n nodes....The 3 nodes will allow
>me to keep complexity down while learning and then i can expand to n nodes
>once i have it down to increase speed.
Good luck.. At 3 nodes, you can just throw the PCs under the table and hook em
up with a ethernet switch.
But, if you find a pallet load of surplus PCs, and want to repackage them a bit
more densely, then the cookie sheet approach is easy.
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