[Beowulf] Efficient UPS Aids Google’s Extreme PUE

Nifty Tom Mitchell niftyompi at niftyegg.com
Thu Apr 2 14:38:01 PDT 2009

On Thu, Apr 02, 2009 at 10:18:39AM -0400, Mark Hahn wrote:
>> April 1st, 2009 : Rich Miller
> was this just a very droll and not very funny april fools article?

This April 1 was full of odd but real announcements.
Strange... perhaps that is the joke in and of itself.

>> uninterruptible power supply (UPS). The design shifts the UPS and battery
>> backup functions from the data center into the server cabinet (see our
> well, that sounds reasonable - I guess the point is just that the right place
> to put a battery is in the ac->dc switching unit.  it's a little strange  
> in that you might hope for some advantages to a large/central UPS, and 
> that it presumes all nodes need power protection, and that the intended 
> runtime
> is fairly low.
> without knowing the numbers, it seems strange to move more degradable
> hardware into the nodes...

I suspect that the UPS component is very short.  i.e. finish the current
search, notify the distributed google world that the 'node' is going
off line and then go off line.  I doubt that the specifications for the
UPS are hours or days the way a national weather center or hospital data
center or other critical resource is specified.   If someone post a pool
for the UPS time factor put me down for 15min.

This does have applicability to Beowulf clustering in the context of
checkpoint and restart if the tiime to checkpoint and tidy up is fully met.
It also changes the external generator power backup requirements from
half wave response to 5 min warm up and switch in for a diesel generator.
Some sites keep their generators (like fireboats) hot to they can run
at full power on a moments notice.

More interesting is the discussion about cooling and the elimination
(minimizatiion) of chillers.

	T o m  M i t c h e l l 
	Found me a new hat, now what?

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