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I'm trying to figure out my colocation needs and one requirement is the power usage of a server. Most colocation providers give you the option of between 0.4 and 1 amps per U server. How should I go about working out how much power a server would use?

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Purchase a Kill-a-watt meter and measure your power in watts and KVA. This device will allow you to measure amps directly. Run the server for a while and record the highest amp draw. That would be the number I would use for the server amp requirements.

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If your servers are powered by 208V a Kill-A-Watt won't work, but there is a solution: Watts Up? sells an 'international' version with C13/C14 connections (perfect for servers.) It also works with 120 and 240V inputs. – toppledwagon Oct 27 '09 at 22:05

What's the model of your box? Power consumption should be listed in the hardware specs of your server. Typically this is an absolute max, meaning that'll be the max load that the server draws under full utilization and during power-up. Consumption during general use is typically lower than the specs list.

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My servers with 870W power supplies routinely consume less than 200W. I never go by the rating of the power supply. Also note that the power supply is (usually) most efficient at 50% utilization. The use of a Kill-A-Watt or Whats Up? meter is highly recommended. – toppledwagon Oct 27 '09 at 22:07

In addition to what squillman said. I know at least Dell has a utility that you put all the models you need into a diagram, and it prints out a report of Max Power, Cooling, etc. by Rack and by server - sorry it's been almost 2 years since i've needed it so i forget it's name just remember it exists. I'd be surprised to find that the other vendors didn't have a utility like that available.

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