[rescue] Deciding how to place machines in a rack...

[Steve Hatle]

On 3/5/08 3:21 PM, "Patrick Finnegan" <pat at computer-refuge.org> wrote:

> On Wednesday 05 March 2008, Earl Baugh wrote:
>> I'll space each machine 1U apart, but I have a question regarding
>> that.
> 
> FWIW, I'd suggest making the machines as contiguous as possible,


I think I'd agree with Pat on this one; I can't see any advantage of getting
air between the systems. The little cooling you would get would be radiant,
and unless you are forcing air through those spaces, it would be minimal.

The machines (should) be designed to pull the air they need through them,
whether from the front or side as the case may be.

As far as using the plexi door, we did an experiment with some of our gear
at a previous job. These machines (Proliants) drew air from the front, and
exhausted from the rear. Air was forced up from the floor under and in front
of the racks. No top fans in the racks.

We used the plexi doors on the front of the racks and used the built-in temp
monitoring in the machines to get a baseline of internal temps. The plexi
doors did have some venting in them, but not much.

We then switched them for the mesh doors that went on the back of the racks,
and left the backs open. The internal temps of the machines went down
between 0 and 10 degrees F, without any other changes to the environment,
etc.

These were 42U racks with the machines and disk trays stacked from bottom to
top with no spaces in between. Never even considered that airspace between
would be necessary- besides, I needed every U of rack space.

So- I don't know how that might effect your decision. I'd say if you like
the plexi door, then use it. If you think 10 degrees is worth it, then you
can modify the door to suit.

Besides, the blinky lights are brighter without the door if it's
colored/smoked plexi :-)

Steve