Energy consumption vs % utilization?
Steven M. Bellovin
smb at research.att.com
Tue Oct 26 20:01:24 UTC 2004
In message <Pine.WNT.4.61.0410261429110.3340 at vanadium.hq.nac.net>, Alex Rubenst
ein writes:
>
>
>Hello,
>
>I've done quite a bit of studyin power usage and such in datacenters over
>the last year or so.
>
>> I'm looking for information on energy consumption vs percent utilization. In
>
>> other words if your datacenter consumes 720 MWh per month, yet on average
>> your servers are 98% underutilized, you are wasting a lot of energy (a hot
>> topic these days). Does anyone here have any real data on this?
>
>I've never done a study on power used vs. CPU utilization, but my guess is
>that the heat generated from a PC remains fairly constant -- in the grand
>scheme of things -- no matter what your utilization is.
>
I doubt that very much, or we wouldn't have variable speed fans. I've
monitored CPU temperature when doing compilations; it goes up
significantly. That suggests that the CPU is drawing more power at
such times.
Of course, there's another implication -- if the CPU isn't using the
power, the draw from the power line is less, which means that much less
electricity is being used.
--Steve Bellovin, http://www.research.att.com/~smb
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