Enlogic : the PUE can be misleading

While PUE does provide an effectiveness metric of the facility services to the IT equipment; it does not provide any meaning in relation to IT equipment efficiency, and in fact can become quite misleading.

“Take an extreme example; imagine a data centre full of thousands of computer servers sitting idle, but consuming energy. Suppose such a data centre has a well-managed facility with a PUE of 1.4; would one believe this is an efficient date centre despite no computing work being done?” quoted Eddie Desouza, Head of Business Operations, APAC for Enlogic.

While reducing total energy consumption is ultimately more important than reducing the PUE, many managers are setting their individual and facility performance goals based on improved PUE, not necessarily reduced energy which is harder to quantify.

“The most energy efficient data centres are actually reducing overall energy consumption and costs by looking holistically at PUE in conjunction with IT performance per watt type metrics.”

Enlogic is now calling for companies to stop using PUE alone but in combination with more modern solutions, like intelligent PDUs, and performance-related metrics to accurately measure energy consumption and enable real energy consumption savings initiatives.

In other words, since the PUE calculation is a ratio of total-energy-Input over total-energy-output; if we take 100% of the input energy and facilitate almost 100% of it to outputs, then a perfect PUE=1 will be achieved.

Nevertheless, if 100% of those outputs are running on idle servers, then it raises another concern.

To measure which equipments should wake up or go to sleep intelligently, one would need to rely on performance-related metrics and intelligent PDUs.

More on the state of data center and other details.