Google's PUE

Alex Rubenstein alex at corp.nac.net
Wed Oct 1 16:04:23 CDT 2008


I only quickly read this, but have the following question, should google
like to answer it...

Of the six datacenters, where are they all physically located?

Someone should get on the bandwagon of having a PUE standard that is
climate based. A PUE of 1.3 in the Caribbean is way impressive than 1.3
in Quebec.

And, why the hell do people use PUE rather than DCIE? DCIE makes more
sense. A PUE of 1.15 is DCIE of .86, which is somewhat easier to
quantify in ones mind. Translation would be, "for every 100 watts into a
site, 86 goes to the critical load."

I'd be interested to hear what economization methods they use. 

And, while they touch on how the water evaporates to cool their
datacenters (a la cooling towers), they neglect to tell us how much
water is consumed and evaporated (in a heated form) in to the
atmosphere.

Don't take this as an attack on Google, but there is a lot more to a
datacenter efficiency analysis than simple stating your PUE and some
other data. For instance, if you have a higher PUE but consume no water,
are you more eco-friendly? What about airside vs. waterside
economization? Is a higher PUE acceptable if the power generation source
is photovoltaic or wind (rather than coal or gas)? Do they do ice
storage? If they are they using river water, what does heating that
water affect?  

It's a good topic to talk about (and something I believe NANOG should
focus on), but I'd love to see more nuts and bolts in the data from
Google. 



> Google has released its PUE numbers:
> 
>   <http://www.google.com/corporate/datacenters/measuring.html>





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