[Beowulf] A Cluster of Motherboard.

Florent Calvayrac florent.calvayrac at univ-lemans.fr
Fri Nov 11 09:17:25 PST 2005

Jim Lux wrote:

> At 06:58 AM 11/11/2005, Robert G. Brown wrote:
>> On Fri, 11 Nov 2005, Jim Lux wrote:
> Home/self built packaging is, I'd venture to guess, a way to do "proof 
> of concept" on a limited budget.  Or, it's a somewhat unique artistic 
> medium.
> Exactly.. I'd say the size of 4-16 (just to keep it powers of 2) nodes 
> is where the "sweet spot" is for proof of concept/hobby/self 
> packaged.  You're still at a reasonable overall power consumption 
> (e.g. you can plug it into one circuit and not start a fire, nor cause 
> your a/c bill to skyrocket). And, it's going to be in the "fit under 
> or next to a desk" sort of size.
> My previous experience with getting moderate quantities of sheet metal 
> enclosures made makes me think that the basic per unit cost of such a 
> thing might be in the $15-20 range, for quantities in the tens or low 
> hundreds.  A few hundred dollars for NRE setup, then the rest is 
> machine time and handling (the raw material is steel, and exceedingly 
> cheap)

We used metal rails in our enclosure of 8 CPUs(about which I already posted
on that list, however I don't think that the student
website about it is still up) to mount the motherboards :  this way, no 
need for a
precise adjustment of the holes, only the rail spacing
has to be measured carefully. We just pierced a number of large
holes at the bottom of the case for vcntilation.

The cluster took us about three weeks of work to build
(thus the money saved on the cases was wasted here) but we learned
a number of things about cooling, and we now have a valuable
exhibit for lab visits and so on. The cluster has now been running
fine for two and a half years : the money saved on the cases allowed us 
to buy
excellent fans and power supplies which is not necessarily the
case with cheap cases sold by assemblers. In a way the three weeks
of work have been compensated by the total absence of maintenance.

No ground loops problems at all ; we used a common rail to plug the
power supplies.


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