Rack or Cabinet

Steve_L_Smith at dell.com Steve_L_Smith at dell.com
Wed Jun 18 08:34:29 EDT 2003

Hi Alvin

Our systems are designed for a maximum inlet temperature of 35C, and a front
to back rise of up to 5C - this is pretty extreme. Normally (good airflow
through the system, not too many cables and a system that is not running at
max - full of disks and memory and really working hard!) we'd expect a 2C
rise, so your 28C in a 25C inlet room is about right. The other thing I
didn't mention is that in a full rack (e.g. 42 x 2P Xeon systems) you would
expect to see up to 11C rise in temperature from the bottom of the rack to
the top - again extreme but worth bearing in mind when deploying full racks
of hot boxes.

Not sure I'd recommend people cutting big holes for the fans - unless it
isn't a Dell of course:-)



-----Original Message-----
From: Alvin Oga [mailto:alvin at Maggie.Linux-Consulting.com]
Sent: 18 June 2003 11:54
To: Steve_L_Smith at exchange.dell.com
Cc: beowulf at scyld.com; beowulf at beowulf.org
Subject: Re:Rack or Cabinet

hi ya steve

On Wed, 18 Jun 2003 Steve_L_Smith at dell.com wrote:

> Trent
> You should take the advice of the system vendor. At Dell (this is not an
> advert:-) we design our systems (as do all tier 1s) for mounting in
> racks (including side panels and doors). This is to ensure correct
> Running something like a Dell PowerEdge 1750 1U DP Xeon in an open cabinet
> is definitely not recommended. The systems are designed to have front to

for the dual xeons or dual-p4s,
what do your normal temperatures run at say using normal 25C or normal 50F
computer room temps ??? 

> back cooling, allowing air to circulate randomly around the sides and tops
> upsets this airflow and will cause the heat within the server to rise,
> possibly leading to over-temperature situations. And if you do not fill a
> complete rack, you should also use blanking panels to maintain the airflow
> also note that this also applies to e.g. a Myrinet switch - you should use
> blanking panels if you do not fully populate the switch chassis.

and if the air in the chassis is meant to go side to side ... the cabinet
airflow should also be doing the same ...

> Unfortunately noise is not something that we can do much about at the
> - putting hot processors in small spaces means we need big/fast (hence
> somewhat noisy) fans to push the air out of our box into your room! 

you can cut some noice by making bigger holes for fans instead of small
holes ...  holes as big as the diameter of the fan blades .. less
interference from the air flow squeezing thru/pass the obstacle

but than again, that's not possible/realistic for making 12" diameter
holes if one is using 12" vent fans

i have a p4-2.0G running at 28C ... am nicely cool and happy...
in normal 25C room temp ... w/ normal fans (noisy) in a 1U mini-itx box..
	-- am thinking the bios sensor must be whacky, but the
	air is in fact cool as is the heatsinks ... and its
	happily calculating away

have fun

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