rack power question

Sun Mar 23 17:36:16 UTC 2008

At 01:14 PM 3/23/2008, Ray Burkholder wrote:

>My desktop has a 680 Watt power supply, but according to a meter I once
>connected, it is only running at 350 to 400 Watts.  So if a server has a
>980W power supply, does the rack power need to be designed to handle
>multiples of such a beast, even though the server may not come close
>(because it may not be fully loaded with drives or whatever)?  Wouldn't it
>be better to do actual measurements to see the real draw might be?

The startup draw can be quite a bit more.  I think before all those 
fancy power saving features kick in, some of the servers we have can 
draw quite a bit on initial bootup as they spin the fans 100% and 
spin up disks etc.
I also find the efficiencies of boards really vary.  In our spam 
scanning cluster we used some "low end" RS480 boards by ECS (AMD 
Socket 939).  Cool to run to the point where on the bench you would 
touch the various heat sinks and wonder if it was powered up.  This 
compared to some of our Tyan 939 "server boards" which could blister 
your finger if you touched the heat sink too long.

         ---Mike 