Cookie policy: This site uses cookies (small files stored on your computer) to simplify and improve your experience of this website. Cookies are small text files stored on the device you are using to access this website. For more information on how we use and manage cookies please take a look at our privacy and cookie policies. Some parts of the site may not work properly if you choose not to accept cookies.

sections

Why PUE is here to stay

  • Print
  • Share
  • Comment
  • Save

Ever since The Green Grid introduced the concept of Power Usage Effectiveness (PUE) in the February 2007 paper Green Grid Metrics: Describing Data Center Power Efficiency there has been widespread debate. To commercial hosting providers it has often been a challenge to cater for customer’s desire to apply a measure for ‘green-ness’. Many providers have older facilities with a considerable investment already sunk and cannot readily re-engineer to chase a perfect PUE of 1.0.

Providers should consider why customers (and more importantly prospects) use and will continue to use PUE to inform their buying choices. It is important to accept that protesting about the use of PUE is not the best strategy.

Why customers like simple metrics
Procurement organizations like to make fact-based decisions. When it comes to facilities there are some obvious measures that apply:

  • What does it cost per month / year per square meter for a set number of years?
  • What does electricity cost per month / year for the equipment I want to house?

There may often be an assessment of other quality factors such as accessibility and remote-hands style services but procurement departments prefer to commoditize the items as they are.

Into this mix comes the need for all organizations (including government) to be green; this is where PUE fits the bill perfectly in that it is well defined and simple to understand – smaller is better.

But PUE is deceptive
Although organizations have technical staff or advisers, there is a limit as to how far these skilled individuals can influence final purchasing decisions. Technical advisers can take some account of the difference between the PUE a data hall may be designed for and that at which it is currently operating but it is unlikely to suit any particular provider. Most procurement departments will insist on treating everyone vendor as equally as possible.

It is interesting to read the 2010 paper on Data Centre Energy Efficiency Metrics on the BCS website in which Liam Newcombe compares DCiE (the inverse of PUE) with other options for more versatile measures to be applied; these include separating out fixed  and proportional measurements). In this paper Newcombe recognizes the key strength of DCiE (and hence PUE) – it can be clearly communicated and explained to senior management.

Although the paper goes on to make some good points about appropriate of metrics to form a more rounded view of the efficiency of a data center these few points from the summary section are the key messages.

In some respects this is akin to the introduction of data center tiering by the Uptime institute; the simple labelling of a facility as being Tier III or Tier IV was a challenge. What has (broadly) happened is that buyers are setting performance measures for availability which cut to the heart with regards Tiering. It is also the case that the ‘equivalent to Tier III’, ‘Tier III’ and ‘Tier IV’ give a good enough sense of the standards to which a Data Centre is constructed that a would be buyer can filter options according to their perceived need.

Is there another perspective?
If we consider that PUE is here to stay at least for the immediate future it must be embraced not struggled against. Consider the following: a buyer is faced with two options for hosting; one has a PUE of 1.6 (but designed for 1.4) the other is 1.5. If everything else is equal then it is true that the facility with the lowest PUE today is the one that is greenest today! There is no argument. A debate can be had over total lifetime of the contract and rates at which data halls get filled but at a moment in time the lowest PUE is the better choice.

If we consider PUE as a market force then, from a buyer’s perspective, many providers have moved from providing a qualified PUE score almost under protest in 2010 to many now leading with their PUE scores. There have been several articles (and not just about Google) about new facilities opening up in the UK with very low PUE. There are many suppliers who have recognised the challenge of established facilities having relatively high PUE and are engaged in multi-year plans to update their infrastructure and drive down the PUE of their hosting year on year.

From a market perspective this is the desired outcome – a constraint drives behaviour that initially resists then is changed. Many organizations now see the goal of low PUE as being an opportunity and not a threat – and that is how it should be.

In summary then, PUE is widely used and will continue to be – this should be seen as part of the modern environment and hosting providers should respond accordingly.

The views expressed above are those of Tony Jones, IT expert at the PA Consulting Group.

Related images

  • Tony Jones, PA Consulting Group

Have your say

Please view our terms and conditions before submitting your comment.

required
required
required
required
required
  • Print
  • Share
  • Comment
  • Save

Webinars

  • Is Hyperconvergence a Viable Alternative to the Public Cloud?

    Thu, 31 Mar 2016 15:00:00

    Enterprise IT leaders are right to be skeptical of such bold claims. After all, is it really possible to deliver an on-premises infrastructure that delivers the same agility, elasticity, and cost-effectiveness of public cloud providers like Amazon Web Services? If you’re following the traditional IT model, with its many siloes and best-of-breed point solutions, the answer is, most likely, no. To truly deliver a viable alternative to public cloud, you need to look beyond traditional IT. Join Evaluator Group and SimpliVity to learn more about how hyperconverged infrastructure can deliver the efficiency, elasticity, and agility of public cloud."

  • "Single Pane of Glass” comes to your Datacenter facility & IT operations

    Wed, 24 Feb 2016 18:00:00

    Join Hewlett Packard Enterprise and RoviSys,as well as OSIsoft, for a webinar hosted by DatacenterDynamics’ CTO Stephen Worn, as they discuss the implementation of the “Single Pane of Glass” solution and some of its resulting benefits: •An estimated 10 Million kWh saved in the first full year of operation •Ability to easily meet “Best-Practices” throughout data center operations

  • Overhead Power Distribution – Best Practice in Modular Design

    Wed, 3 Feb 2016 16:00:00

    Overhead power distribution in your data center offers many attractive possibilities, but is not without its challenges. Join Starline's Director of Marketing, Mark Swift; CPI’s Senior Data Center Consultant, Steve Bornfield; and University of Florida's Joe Keena for an exploration of the options and some of the pitfalls, supported by real-life examples from the field.

  • White Space 29: See the diagram

    Fri, 29 Jan 2016 10:40:00

    Peter is investigating DevOps, Bill looks at security while Max is stuck on the infrastructure level

  • White Space 28: The good, the bad and the ugly

    Thu, 21 Jan 2016 12:10:00

    Join the DCD team again this week, as they discuss AMD's ARM based efforts, waste heat, BT's EU deal and cloud for Canucks and much more! Enjoy.

More link