[Beowulf] powering up 18 motherboards

Alpay Kasal eno at dorsai.org
Sat Feb 19 02:58:59 PST 2005

Thanks to all for the info over the past few days. I decided to write a WOL
app that turns the machines on from a windows box on the network with a user
defined delay. I'll stick it on the web if anyone is interested in taking a
look at it. I plan to add the ability to selectively shut machines down too
(since the whole thing doesn't do much good from a cold boot). 

@Eric Machala and David Mathog
Thanks for the info on the UPS's. I will be looking into some of the bigger
refurbed APC's on eBay (I don't have 240v here though). I'll leave some
safety room on the circuits for peaks, now I figure I'd want the UPS's to
get me through the problems RGB was describing - I don't get many brownouts
in NY with our underground cabling but that occasional power hiccup would
drive me nuts.

@Patrick Michael Kane
I must say that I have NOT been cranking away with the 3D apps I'll be using
regularly. Just trying to put load on the cpu's for my tests. I'll be
properly set up to do everything right over the weekend. I needed to first
finish the build-out for cooling and these power issues. I'll be sure to
report back with my details.

@Jim and RGB and Bari
Understood. Loud and clear. No ganging of circuits. I didn't know if it was
easy run in parallel to support bigger peaks. I won't be touching whatever
is behind the circuit breakers by myself.

@RGB again...
VERY informative stuff about power and PS's. Thank you.


-----Original Message-----
From: Eric Machala [mailto:emac at cybergps.net] 
Sent: Friday, February 18, 2005 2:37 AM
To: Alpay Kasal; 'Jim Lux'; 'Dean Johnson'
Cc: beowulf at beowulf.org
Subject: Re: [Beowulf] powering up 18 motherboards

This is not true the Ups will not draw ever any more from the wall that its 
is set to, ups has a set trickle rate that is able to be set  to a cost 
effective trickle rate unless it is load overloaded it, if this is the case 
it is double the trickle rate becuase systems wants to restore full battery 
before power drain err loss of power.... i could get the actual specs on 
this but for your actual needed load if u were in a 50-65% load im sure 
there would be no spikes in power draw over normal trickle

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