[Beowulf] bring back 2012?

[Stu Midgley]

I measured the power draw of our 2RU 8 phi nodes with and without fans...
the fans draw about 20% power.

On a 2200kW node that's considerable.

On Tue, Aug 23, 2016 at 5:36 AM, Mark Hahn <hahn at mcmaster.ca> wrote:

> Extra, the direct contact cooling stuff must still have the fans in the
>> nodes to keep the dimms/disks/power supplies cool... thus use considerably
>> more power than nodes without fans.
>>
>
> why do you say "considerably"?  1u muffin fans are annoying and not that
> efficient, but even 1U could still use blowers.  and it's not as if
> you need a lot of airflow to keep 5-20W of support hardware cool.
> (that would be for non-extreme numbers of disks/dimms/nics - though it
> occurs to me that motherboards also have some power regulation in them,
> and if 2 sockets are drawing 250w, then 90% efficient regulation would
> still mean 28W extra heat to dissipate.)
>
> iirc a typical 1U fan dissipates up to ~3W, but that's only when running
> full on (screaming 14krpm...).  not to mention the wide availability of
> simple 4-system-in-2u chassis (more efficient fans).
>



-- 
Dr Stuart Midgley
sdm900 at sdm900.com
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