Data center facilities pro

Aug 14 2008   9:28PM GMT

Uptime warns data center pros against being benchmarked on PUE

Matt Stansberry Matt Stansberry Profile: Matt Stansberry


Uptime Institute executive director Ken Brill warned panelists at an online seminar today to be wary of very low Power Usage Effectiveness (PUE) ratios touted by some data center operators. “If your management begins to benchmark you against someone else’s data center PUE, you need to be sure what you’re benchmarking against,” Brill said.

Brill said he’s seen companies talking about a PUE of 0.8 — which is physically impossible. “There is a lot of competitive manipulation and gaming going on,” Brill said. “Our network members are tired of being called in by management to explain why someone has a better PUE than they do.”

If you’re going to compare your PUE against another company, you need to know what the measurement means. “You need to know what they’re saying and what they’re not saying,” Brill said. “Are you going to include the lights and humidification system? If you’re using free cooling six months of the year, do you report your best PUE?”

Brill conceded that The Green Grid’s PUE whitepaper has gained traction in the industry, spurring more action and debate than any other efficiency effort so far. But Brill takes issue with the measurement’s use of the term “power”. According to Brill, the fundamental problem with PUE is that it’s a snapshot in time. Power by definition is a spot measurement, Brill said. Power over time is “energy”. So power is measured in kilowatts, energy is measured in kilowatt hours.

Proponents of PUE like Microsoft’s Christian Belady have advocated measuring PUE over time, but Brill said that is not expressed explicitly in the standard.

I think it’s a bit of a stretch to assume C-Level execs are even aware of PUE (let alone calling data center staff out on the carpet about it).

I recently wrote an article about a data center manager that made huge efficiency improvements at a massive facility, saving hundreds of thousands of dollars through engineering projects. I asked him what his CIO thought about the data center efficiency he was achieving, and he told me the CIO had no idea. He’d never actually met the CIO…

Nonetheless, Brill makes a very important point. The first goal of PUE is to make a ratio to improve on internally. But the larger goal is to use the metric to compare data centers — as a benchmark against competitors, or as a way to compare various configurations, geographical locations, and technologies. Without standardization, comparative measurements will be meaningless.

Are your executives measuring you against competitors’ PUE? We’d like to hear from you.

4  Comments on this Post

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  • FacilityGuru
    With so many possible variances between Data Centers how can one truly 'Match" another Data Centers PUE number. I have been working diligently to improve ours, but isnt that the bottom line? Getting the most from your center as possible is the ultimate goal. If competition works, than so be it, I'm up for a little competition. He who wins, saves money and that's the goal. Respectfully RPeters.
    95 pointsBadges:
  • KozmicKid
    I've always had my doubts about PUE. For one thing, a data center manager can consolidate applications on a smaller number of servers, thereby reducing power consumption, but if it puts his UPS, power distribution, and cooling lower on the efficiency curve, his PUE gets worse.
    0 pointsBadges:
  • Aernoud
    I agree. A PUE value is meaningless without the information on how (and when) it is measured. Specially in the DataCenter Housing area I have lots of question marks on the PUE value they advertise with. In my oppinion datacenters should base their PUE value on the total energy spending per year. Commercial Datacenters should make (audited) anual statements that show their yearly energy spending (with specifications and PUE values) over de years. This way they can also show improvements they have made. If you ever have to negotiate with commercial datacenters. And in their offer they advertise PUE values that you feel are on the optimistic side. Just ask them to translate this into a financial cap on the electricity bill they send you. So with a PUE of 1.3 they can never bill you more then .3kWh for every kWh your ICT is consuming. Usually you will then find soon enough if the PUE value is firm or not.
    30 pointsBadges:
  • Jbeltran
    Check out this page for more on [A href=""]data center design standards[/A].
    0 pointsBadges:

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