With the energy required to run the IT equipment in the denominator, PUE as an indicator of energy performance is a flawed measure. Yes, it highlights the auxiliary loads, which are part of the total energy in the numerator and are important to minimize, but in terms of energy use, auxiliary loads should not be the only focus. Making matters worse, the industry has set the goal to be simply reducing PUE, bragging about low PUE, reinforcing the efforts on auxiliary systems and making is seem that when they reach some minimum, their job will be done. From an energy perspective, in a word, this is NUTS. Low PUE is not the measure of data center efficiency because it does not measure energy per unit product delivered, which is data processing. With server utilization rates often at 10% or less, and fully idle servers estimated to number in the millions, much of the energy going to the IT load is pure waste. Addressing that issue will have a much greater impact on energy use, all while INCREASING PUE, which the industry is training everyone to believe is bad! From software that manages server utilization to new hardware and chip designs that greatly reduce server energy consumption, there are many new technologies which are more than ready for an industry wide roll-out – if only they would stop worrying about lowering PUE and start focusing on reducing the TOTAL ENERGY required to handle and deliver their product.
Taking a Truly Holistic View of Data Center EfficiencyData Center Knowledge, November 18, 2013
The word “holistic” comes up frequently in the data center industry, with industry leaders and trade publications urging operators to take a more comprehensive view in their journey to improve energy efficiency.
This idea has been leading to some significant advances in energy efficiency at the facility level: better cooling systems, power distribution units, universal power supplies, backup power generation, and so on. These kinds of advances have undoubtedly had a positive impact on energy waste at datacenters. In fact, the average Power Usage Effectiveness [PUE] in the industry dropped from 2.7 in 2007 to 1.65 in 2013.