[Beowulf] VIA cluster server reference design

[Unknown]

The C147 and C247 do have problems if you stack them tightly.  If you
put a half inch or so of space between them they will be much cooler.

I don't use a case for stacking nodes..

I have stacked V8000A's and no overheating.

BUT.. 

The boards are stacked with aluminum standoffs and each stack of 3
motherboards has a metal plate under it (and on top) which is also
connected to the metal standoffs.  

A lot of heat is dumped to the copper ground plane inside the via
motherboards. That ground plane is thermally connected to the copper
pads at the mounting holes of the board. Using a thermally conductive
material such as aluminum, to stack the boards well remove quite a bit
of heat.  


Bolting each board to an aluminum plate using aluminum standoffs and NOT
using plastic standoffs will provide a surprisingly good thermal path to
the chassis, thuis allowing for better cooling.  

If you are using boards with quite a bit of power dissipation you will
need to add a fan to circulate air across the board to help move any
excess heat.. 

For the fanless boards you need to be sure you have the metal plate
between the boards to reduce adjacent boards heating each other due to
radiation, and to help move heat away more quickly. 

Do be sure to allow for adequate air circulation... stacking the boards
vertically like so many library books on a shelf will allow convection
to assist in cooling. 

My present mini-itx cluster is two stacks of 6 boards bolted to a 7U
rack panel. heat is not an issue. The only fans present are on the
cpu's.


Glen


On Wed, 2005-10-19 at 10:45 -0700, Joel Jaeggli wrote:
> On Wed, 19 Oct 2005, Eugen Leitl wrote:
> > FYI, I run a dual-mini-ITX system in a Travla C147, and it
> > doesn't have sufficient airflow to be stacked in a rack
> > without some dead space. Even then some extra fans might
> > be required.
> 
> mini-itx motherboards have been designed fairly effectively to resist 
> stacking. with  most of the airflow either down onto or away from the top 
> surface of the mainboard, and a huge block of connectors on the back. I 
> have 8 c136's (not for a cluster), they are cool and almost silent, but if 
> you stack them they'll overheat almost immediatly.
> 
> >
>