[Beowulf] The fan from hell

[Joel Jaeggli]

On Thu, 9 Jun 2005, David Mathog wrote:

> Today I distributed database fragments out from the main server
> to the 20 compute nodes.  This required the server to run gunzip
> pretty much continuously for a couple of hours. The net result of
> which was that CPU1's temperature rose from 55C to 60-61C.
> Normally the fan on CPU1 sits happily at 5033 RPM. However
> today it started to slow down.  In fact it slowed down below
> 3000RPM, which triggered an automatic shutdown of the server.
>
> After a bit of experimentation I've now determined that
> this wasn't a coincidence. This CPU fan really does run
> slower when the CPU gets hotter.  It takes a
> few minutes before it starts to slow down, but slow down it
> does.  Not exactly the desired response for a fan on a hot CPU!
> This is on an Athlon MP 2000+ processor and the fan is Dynatron
> model that AMD used with the boxed CPU.
>
> Any of the system vendors (or anybody else) out there have a
> preferred brand of 60mm fan that doesn't slow down at 60C?

Delta Electronics FFB0612EHE is a 60mm 8000rpm fan rated for 50.15 CFM at
54.5dba (freaking loud) 1.2a draw

Sunon GM1206PTBX-A is a 60mm 5200rpm fan rated for 26.2cfm  at 38dba .25a 
draw.

The delta's are commonly found as exhaust and intake fans on 2 and 3u 
enclosures, you wouldn't want to share an office with them, but they are 
heavy duty high volume and reliable.

> Thanks,
>
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
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Joel Jaeggli  	       Unix Consulting 	       joelja at darkwing.uoregon.edu
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