Data centre efficiency: It’s time we noticed the elephant in the room
20-07-2012 - John Hatcher
At the moment, regulators across the world are struggling to find ways to measure how energy efficient a data centre is by measuring how the ‘useful work’ it delivers compares with the energy consumed. The idea being that data centres can then be given a ‘score’ which says how energy efficient they are – or not – and the regulators can influence the market.
Whilst I agree that data centres need to become more energy efficient, I think that in the quest to find one , all-encompassing energy efficiency metric, we’re being side tracked from the main issue and ignoring the big opportunity. For me, the elephant in the room is that data centre environments have traditionally been designed, developed and managed as if their workload is static – and that is what we should be concentrating on first before we start imposing a metric.
To explain this, let’s draw a comparison between how a desktop PC or laptop uses power and how a data centre uses energy. In recent years, chip vendors have worked hard to make laptops and PCs smarter in the way they use power – laptops and tablets in particular need a long battery life otherwise they won’t sell. This means that if you’re doing something quite complex on your PC – like editing video or watching a movie – the PC draws more power than if you’re just browsing the web or working on a word document – and in standby mode, a PC hardly uses any power at all. Unfortunately, data centres don’t work like this.
Let’s say we have a corporate data centre which hosts a customer contact platform with a web presence and a few thousand call centre operators. On a Monday morning, it might be handling 50,000 calls and 100,000 web users every hour. It might be using a lot of power – but it’s doing a lot of work. However, if we return and measure energy consumption at 4am on a Sunday when there are no phone customers and only a few web users – it will drawing almost the same amount of power.
To use an analogy, if a data centre was a car we would not be able to turn the engine off and it would use almost the same amount of fuel idling on your driveway as when it was carrying five people, speeding along the motorway at 70 MPH. To continue the analogy, if you were concerned about your car’s fuel consumption – which you really should be – you’d probably ask why you couldn’t turn the engine off and why your car needed all that fuel when it was stationary. You wouldn’t ask the garage to tweak the engine to make it run more efficiently at 70 MPH – but this is the equivalent approach our regulators are taking in searching for a metric to measure how efficiently data centres run at maximum load.
For me, it is less important how efficiently a data centre operates when working hard on a Monday morning. I am far more concerned that we understand how inefficient it is when it’s doing nothing – and that we then minimise this inefficiency. However, to date, the data centre industry has a poor record of coming together to address this challenge.
Whilst some companies have recognised this issue and started making more energy efficient servers, much of the equipment in a data centre still draws close to full power all of the time. There’s no one single piece of equipment that’s going to solve this issue and no one vendor or department that is solely responsible – there’s no magic bullet. To address this issue we need a paradigm shift in the way that we as an industry think about the design and deployment of data centres. From the mechanical engineering to writing our software, we need to ask: “how much power, data centre capacity and cost will this waste to do nothing?” And as we ensure every device is tuned to manage its energy consumption at a lower load, we’re also going to see data centres becoming cheaper to run and more efficient at full load.
But to spur the industry into action, we need to create an informed market. We need to make the issue of waste energy and cost clear to the business. Every finance chief needs to know how much energy each data centre service is using when it’s working at full capacity as opposed to when it’s idling for them to be able to make a decision which service is worth the cost – and which isn’t. Only then can they make an informed choice about which data centre services they are happy to spend the money on, which ones they might want to spend less on and which can be turned off altogether. And it’s only when this happens that the market will start to change.