Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

As part of a sustainability project I have been requested to measure the PUE of our server room. We have gross power usage figures from the UPS (and seperate supply meters) but nothing else. How in a practical way should I go about getting the rest of the data I need?

share|improve this question
Do you mean efficiency? – Mark Henderson Aug 25 '10 at 2:04
Some of the info here may help out… – Kara Marfia Aug 25 '10 at 2:06
As a first step, and generic rule of thumb, older servers do not support dynamic power reduction and thus burn more electricity than newer (and usually more powerful) servers. Also consolidation through virtualization generally reduces your server electric bill by 2x for small installations and 6 to 8x for larger server rooms. – Chris S Aug 25 '10 at 2:27
Thanks for the info FarSeeker, Kara and Chris. To clarify PUE is the ratio between the total power consumed by the server room / data centre and the power actually used by the servers. It is a measure of datacentre power efficiency. – Charles Dean Aug 25 '10 at 4:28
up vote 2 down vote accepted

To measure the actual power usage of a server, get an electric meter like the Kill-A-Watt P4320; it costs about $60 and will measure the power usage of most typical servers (monster servers and 48v need not apply).

Also, Jeff's blog article "Why Estimate when you can Measure" has some good information.

share|improve this answer
Developing from Chris S's answer, I have found you can buy PDUs with inbuilt watt meters that either display on the PDU or the information can be sent to a server for consolidation – Charles Dean Oct 20 '10 at 3:17

There is some great information about what Power Usage Effectiveness (PUE) is, how to practically measure it, and even a simple calculator found here.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.