More data centres means more energy consumption – but where is the demand coming from?

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While data centres are set to grow exponentially over the next few years, PC sales are in long term decline. Fewer and fewer are being sold and, despite a brief boost in sales towards the end of 2014, market experts are predicting a continued decline in 2015. Here Paul Ryan, UK Segment Sales Manager for Eaton, explores why this is and the potential impact on the data centre market.

There are plenty of reasons behind this, from PCs being 'good enough' at common tasks such as web browsing and basic productivity, to lasting much longer than before, through to the advent of smartphones and tablet PCs. More recently economic factors and concerns over currency strengths have reportedly been having an impact too1. Whilst a reduction of 4.9 per cent in 2015 - according to IDC's latest report2 - may seem mild, it is part of a long term downward trend which is far from insignificant.

The chances are that the next few billion people to get online will have never owned a PC – they'll be using a phone – smart or otherwise – or a tablet PC. These devices tend to outsource data storage, processing and the like to data centres, keeping the cost of the device in users' hands down, and aggregating the compute and storage in data centres.

Couple that to the massive increase in machine to machine communications and the any-day-now advent of the Internet of Things, and internet traffic – and the load on data centres – is going to shift inexorably.

It's difficult to be specific about the changes that this will wreak, but one thing is clear: a lot of the data processing tasks traditionally done on a desktop PC are now taking place on servers somewhere else in a data centre.

This explains the stupendous growth in data centre space over the last few years. In-data centre Network traffic is a demonstration of how much information is being dealt with by data centres, and Cisco's Visual Networking Index predicts a 25 per cent compound annual growth rate in data centre network traffic between 2012 and 2017, from 2.6 Zettabytes a year in 2012 to 7.7 Zettabytes in 2017. What's a Zettabyte? It's a million Terabytes, or a thousand Exabytes. In 2006, the combined capacity of all of the computer hard drives in the world was estimated at 160 Exabytes – just 16per cent of a Zettabyte.

An example: using a smartphone, someone shoots a video. They edit it using a web-based app, and upload it to YouTube. The processor in the phone is not used to render the video after editing – all the heavy lifting and publishing is carried out after the video file is uploaded to the data centre for distribution on the web.

Environmentally, this is actually a good thing. Rather than millions of distributed nodes processing data, and sucking up electricity individually to do so – the client is a low powered device, and the cooling, power management and other elements can be centralised in a data centre.

This makes for far more efficient use of energy – well, at least in theory. In reality, a badly set-up data centre, or an old one, or one that is sited somewhere where power is cheap and green concerns are less of an issue, can be pretty profligate when it comes to wasting energy.

It also changes the dynamics of clients and servers. Leaving a desktop PC switched on 24 hours a day consumes far more electricity than keeping a mobile phone or tablet ticking over. The flipside of that is that the energy use is moved elsewhere – to a remote data centre – where the end user isn't paying the electricity bill.

The good news is that data centre operators are wise to this, and are changing what they can affordably change in existing facilities, while building their next data centres with an eye to energy efficiency. The easiest and quickest change (to a certain extent) is to lower the cooling requirements. In a data centre with an average PUE of 2, 40 per cent of the energy used goes towards cooling. Reducing the amount of waste heat put out by the IT (which, itself, uses 50 per cent of the electricity in this calculation) and switching to more efficient ways of removing heat can lower a big slice of a facility's energy bill.

It's fair to say that changing behaviours and end user devices are going to add up to more data centres. Because usage patterns change with this, it's also going to mean that those data centres will be built to handle different loads than those of old.
Finally, energy is becoming more of an issue. In Europe, where electricity costs rise year after year, this means more and more power-efficient data centres. In Asia, where coal and energy are both relatively cheap, but power networks are not always reliable and electricity supplies are subject to brown-outs, this makes for an increased focus on getting reliable and smoothly-delivered electricity into the data centre. In different parts of the world, data centre energy is an issue for very different reasons. In some places, costs are less of a consideration, but reliable, even supply is a priority.

The power chain, which, in that fictional data centre operating at a PUE of 2, makes up the remaining 10 per cent of energy consumed – the UPS isn't running in its sweet spot, so lots of power is going to waste before it even reaches the equipment it's meant to power and protect. The UPS has to be more efficient, and can be – we're looking at less than a 1 per cent energy loss in a UPS employing Eaton's energy saver system (ESS) technology. Elsewhere, local regulations, markets and considerations add a further layer of complexity.

If you didn't think the slowdown in PC sales affected every corner of the IT world, then think again: it changes how data centres operate, and it changes the loads placed upon them significantly.



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