[Discuss] Server Room Power

[blu at nedharvey.com (Edward Ned Harvey)]

> From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
> bounces+blu=nedharvey.com at blu.org] On Behalf Of Matt Shields
> 
> A long time ago I got fed up with trying to calculate amperage, so I
> invested in a clamp on ammeter.  Then I test my servers when I get them
and
> record the high and average usage.  

This is an excellent practice.  I have been using kill-a-watt, but the clamp
is more convenient.  Besides knowing the A, you also want to know the VA and
W so you can spec your UPS appropriately.

One thing to be keenly aware of is that power draw of a server is variable.
To reach max power, you need to find ways of stressing the high power
components - Usually the CPU and GPU (if any.)  But a "while 1 { ; }" loop
will not stress much of the cpu, so it doesn't do a good job of reaching max
power.  The best stuff will be things like the AES instruction set, and
generating random numbers and doing parallel compression.  Get the max power
of the system and fluff it a bit.