[74992] in North American Network Operators' Group
Re: Energy consumption vs % utilization?
daemon@ATHENA.MIT.EDU (David Lesher)
Tue Oct 26 20:11:17 2004
From: David Lesher <wb8foz@nrk.com>
To: nanog@merit.edu (nanog list)
Date: Tue, 26 Oct 2004 20:12:46 -0400 (EDT)
In-Reply-To: <417EB13A.7040200@he.iki.fi> from "Petri Helenius" at Oct 26, 2004 11:19:06 PM
Reply-To: wb8foz@nrk.com
Errors-To: owner-nanog-outgoing@merit.edu
Speaking on Deep Background, the Press Secretary whispered:
>
>
> You should be able to pick up simple current / wattage meter from local
> hardware store for $20 or so. That will tell you that on a modern
> dual-CPU machine the power consumption at idle CPU is about 60% of peak.
> The rest is consumed by drives, fans, RAM, etc. As wattage the
> difference is 100-120W (50-60W per cpu)
Bogus data alert....
A ammeter will tell you amps. But in the world of switcher power
supplies, that does not beget watts. [Why? is an exercise for
the student. Start with "power factor" and "VARS" and worry about
asymetric loads...]
If you want to talk watts, as you must to worry about HVAC,
or really watt-hours... acquire a power company type meter - in
glass with a whirlygig. Put it in a meter box with plugs. [See
your local eletrical wholesaler..]
(The rotating disk watthour meter is amazingly accurate under
almost any kind of load waveform. Only time-of-day metering has
spurred the utilities to replace them.)
Plug the machines into it; it into the wall. Note the numbers
and the time, and come back in 24Hours.
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
