More heaven, less hell for tomorrow's data centres

There's a lot being said about energy consumption in the data centre, and how inefficient - and expensive - it's becoming at the same time.

The loudest noise seems to be coming from the doomsayers - the 'fire and brimstone' brigade that berate the high cost of powering and cooling the data centre. It seems to be the politically correct message to be saying that data centres are inefficient, with some pundits going as far as saying that data centres are the largest IT industry contributors to global warming.

I suggest we not add to the hype and focus on the facts. Yes, data centres are consuming more and more energy, but they are doing it more efficiently than ever before. The real issue is that demand for computing power is doubling every four to five years.

To address this demand, data centres are becoming larger and more densely populated, and therefore require more energy. In parallel with this surge in demand, our industry is responding with IT equipment that requires less energy per cycle, and new approaches to solving the power and cooling requirements that further improve data centre efficiency compared to its total output.

While IT equipment manufacturers take most of the blame for this situation, they also don't take any credit for the efficiency improvements they have made, and continue to make. Instead they point fingers at the inefficiencies of the cooling process, which in turn leads to recriminations for power and cooling vendors for all the wrong reasons.

So let's set the record straight:

1. Approximately 50% of the power to a data centres is for the IT load with the remainder being for the support infrastructure (cooling, UPS, power distribution, lighting, etc). This is in a well-designed and maintained data centre using typical IT equipment and power/cooling infrastructure.

2. The average IT server power supply is 80% efficient but the typical server utilisation is only 15%.

3. Using this example, if a server draws six megawatts from the utility, three megawatts is for the IT load. At $0.10 per kilowatt-hour the utility bill is more than $5 million per year.

4. An improvement in the server utilisation rate via virtualisation to 30% will result in annual savings of over $2 million per year provided the unused servers are turned off.

5. A 10% improvement in the average server power supply to 88% (92% efficient power supplies are available) results in over $500,000 per year in savings. To attain the same savings by improving the cooling system efficiency requires a 30% efficiency improvement, which can be achieved with a next-generation supplemental cooling system.

There are clearly two approaches when it comes to power and cooling in the data centre. There's the 'doom and destruction' school that takes a dim view of power inefficiencies, and then there's the other, more logical approach that engenders real savings by applying commonsense solutions to the problem.

About the author: Peter Spiteri joined Emerson Network Power in 2003, bringing with him more than 20 years of experience in marketing management, IT and engineering. He is currently the marketing manager, Emerson Network Power Australia.

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