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

Brian Deloria bdeloria at gmail.com
Wed Mar 5 16:26:51 CST 2008

I can see this making sense and being true for Steve's post definately with
some proliants coming in at 7u.

Does this also hold true for 1u servers, something that's higher density

That was always where I'd see it the most.

If we're talking about just relying on the fans that are internal to the
machines does having spaces matter?  i.e. no forced air up through the floor

I know most manufacturers when you replace a drive on a machine want you
either to replace it immediately with another or with a filler.  The ibm
bladecenter equipment I worked with years ago even went so far as there were
fingers that would spring up from the bottom and down from the top to impede
air flow through the voids in the chassis when a blade was removed.

I lost a good bit of hearing from those fan's too.  any computer that has
"Accoustic Attenuator" as an option is pretty freakin loud.



On Wed, Mar 5, 2008 at 3:52 PM, Robert Darlington <rdarlington at gmail.com>

> Oh man, everyone at a previous job (national lab) would insist on
> putting spaces between servers until I ran a simulation with COSMOS
> FlowWorks and showed them their mistakes.  This is terrible for
> cooling systems.  You guys are absolutely right about dead air space
> insulating the heck out of machines.  The only way this makes sense is
> if you have forced air coming from the front of the rack, such as a
> fan or chiller unit.
> Nevermind you waste a lot of rack space when you leave gaps between
> servers.
> -Bob
> On Wed, Mar 5, 2008 at 2:40 PM, Steve Hatle <shatle at nfldinet.com> wrote:
> > 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
> >
> >
> > _______________________________________________
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