Google's PUE

Alex Rubenstein alex at
Wed Oct 1 22:22:19 UTC 2008

> Google not counting electricity losses from power cords etc gives the
> image that it doesn't really want to account everything and want to
> skew the numbers as much as possible.

I don't agree with this.

It is commonly accepted that when computing DCIE/PUE, the point of "demarcation" (used that term for the telco crowd) is the receptacle. If they did not include losses in transformation, UPS, distribution, etc., then I would agree. But they seem clear about that in the discussion.

> I would be far more interested in a metric that shows the amount of
> power used for each MIPS of CPU power (or whatever CPU horsepower
> metric other than clock speed). And also amount of power used for each gbps of
> telecom capacity USED.
> Another metric would be how much power is used to store how many
> terabytes of data on disk. Disks consume much power too.

I think you mean "energy", not telecom. While what you ask for is very important, that is generally a function of efficiency of a piece of equipment closed to the consumer. In other words, how efficient a Dell is vs. a HP or something. These things do not relate to the definition of PUE/DCIE.

> To me, it seems that PUE is just a metric of how efficient the air
> conditioning is. 

This is the point. It's a metric of the FACILITY, not the COMPUTATION.

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