Green IT & Green Hosting

Down on the Server Farm

02/08/10

With some estimates suggesting that the energy used to cool IT systems accounts for nearly half the cost of running a data centre, something has to give – and soon.

Analyst firm IDC has estimated that revenue for the worldwide storage services market will have grown to $35.3 billion by 2011 as more files are created and kept. Where is it all coming from? Look only at the email boxes now creaking with audio, video and enormous PowerPoints, and you will see a technology bursting at the seams. And then there are the CFOs and their teams making financial statements available via live audio casts and downloadable podcasts, heaping on the data misery.

The downside can no longer be ignored, says IDC. “The fact is that enterprises have no choice but to improve energy efficiency as increased usage puts a strain on corporate data centres and their finite and expensive power supplies. Failure to manage the impact of the data explosion could, before long, even stem the ability of organisations to compete and innovate effectively.”

Slowly the negative impact of the data explosion has been understood and moves to reduce carbon emissions - without sacrificing availability for users, optimum operational continuity of services or cost control - are well underway. The fact is that it’s unrealistic for enterprises to rip out their existing IT infrastructure and start over, both in terms of cost and practicality. The only realistic option is creating a more energy efficient infrastructure.

Unchecked, data centres’ thirst for power promises to produce arguably the biggest single sustainable energy challenge facing the business world. “A recent survey found that just one UK data centre, from a total of over 1,500, uses more power in one year than a city with a population of over 280,000 people,” states IDC.

Another US survey found that even a 30,000 square foot data centre, by no means a monster, will now support 1,000 server racks. “Depending on their power density, typically 150 to 200 watts per square foot, this translates into a site with a 12 mega watt power demand when cooling power is factored. In the US, with maintenance and amortisation charges added, such a data centre would generate an operational bill of as much as $4.2 million. Europe’s higher electricity prices could add a further 30 per cent to the total.”

Yet the initial response to the data explosion focused exclusively on the emergence of faster equipment at lower prices. “The honest truth is that the environmental impact of the investment was not perceived to be a huge issue,” adds IDC. “Things have changed dramatically in a relatively short space of time. Twenty years ago, chips consumed no more than eight watts of power, but today 110 watts is far from unusual. This phenomenon, christened the ‘underbelly of Moore’s Law’, along with new developments like blade servers, which can increase the concentration of processing power, and therefore power demand, eight times per square foot, are conspiring to accelerate the problems.”

The latest high density servers, working with inefficient infrastructures, are literally threatening to go into meltdown. A report by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has revealed that between 43- 65% of data centre energy is used to power hardware equipment, between 20-25% is used to power cooling systems, and between 1-3% devoted to lighting.

Another IDC report found that US companies spent approximately $5.8 billion powering servers in 2005 and another $3.5 billion keeping them cool. The authors estimated the total cost of the equipment at $20.5 billion.

The spiraling costs are compounded by a reliance on old fashioned and inefficient infrastructure. The much respected Lawrence Berkley National Laboratory believes that every watt consumed by a server is matched by supporting infrastructure that includes, but is not restricted to, cooling. “The combination amounts to a dizzying level of energy consumption that, given the current state of the energy market, has the potential to bring businesses to their knees,” warns IDC.

For data centre operators struggling with the escalating costs of containing the heating demands of increasingly powerful server equipment, new solutions are vital. Indeed, the whole data centre conundrum has become so problematic of late that some facilities have been unable to add new equipment, because they have reached the limit of their power and cooling capacity.

By some estimates, the energy used to cool IT systems accounts for nearly half the cost of running a data centre. The amount of energy consumed by data centres in the US, for instance, doubled between 200 and 2006 – and could double again by 2011, if practices aren't improved, according to the US Department of Energy. The root problem, as anyone running a data centre will be only too aware, is that server equipment in data centres needs to be kept within a certain temperature range. Hardware can fail if it is too warm, but overcooling wastes energy. Still, most data centres err on the side of caution and cool their equipment more than they need to.

However, the technology to overcome these problems is advancing all the time, on many fronts. A team of engineers led by Lawrence Berkeley National Laboratory, working with Intel, Hewlett-Packard, IBM and Emerson Network Power, has successfully tested a new system they believe could greatly improve the efficiency of data centre cooling. Essentially, they have been experimenting with a way to deliver just the right amount of cooling to computing equipment. They fed temperature readings from sensors built into most modern servers directly into the data centre building controls, allowing the air conditioning system to keep the facility at just the right temperature to cool the servers. It's a simple idea, but something that hadn't been achieved before. IT and facilities management systems have historically been managed separately. Computer Room Air Handlers (CRAH), basically large air conditioners, are most often controlled using temperature sensors located on or near the CRAH air inlets.

That's the way 76% of data centres do it, according to an end user study cited in a white paper about the experiment. A further 11% of data centres are said to place the sensors in the cold aisles between the server racks, which is better, but still not ideal. Linking the IT equipment directly to the cooling systems represents "the most fruitful area in improving data centre efficiency over the next several years," according to the white paper.

A fundamental problem is that most data centres today are overcooled, says the study. For example, it found that 90% of respondents keep their data centre at least 5oC below the upper limit recommended by The American Society of Heating, Refrigerating and Air Conditioning Engineers, which publishes data centre temperature guidelines. Adding even a few degrees of extra cooling can be expensive.

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