Wednesday, February 11, 2009

Energy Efficient Trends in the Data Center

Written by Rakesh Dogra

In the good old days, the main focus of staff and management in the data centers was to have maximum uptime of the data center - come whatever may. The green trend was nowhere in sight. But things change rapidly in the IT world and the current scenario is quite different from old days.

Of course having the maximum possible uptime for a data center is still one of the primary concerns, but nowadays and dozen other things also need to be considered at the same time. These are mainly related to increasing the energy efficiency of the data center on the whole. One simply needs to take a look at the rising energy consumption of data centers and it is expected that by the year of the first decade of this century, power consumed by data centers in the United States would be approximately 3-4% of the entire power consumption of all other consumers put together. To give you an idea in terms of absolute numbers it was found that in the 2005 nearly 45 billion kilowatts of power was consumed by servers in the US. If you apply the math then you will find a very large number.

In the light of the above information it is certainly useful to know what is being done regarding energy efficiency in the data center industry. Though there is currently a lack of a uniform set of standards which define the degree or level of energy efficiency of a data center, still several attempts are being made in this direction and hopefully the situation will be much better in the future.

As of now there are attempts to set standards by following certifications such as LEED which is mainly concerned with designing buildings which are energy efficient from different perspectives such as cooling, air-conditioning etc. There are various levels of certification and the exact requirements vary with the level of certification required. Another such certification is the EPA Energy Star certification which is used to rate servers based on their efficiency.
Several tools and techniques are available which help to carry out a proper energy analysis of any given infrastructure and they can be used to gauge the energy efficiency of the data center. These tools and techniques use various methods such as thermal mapping of the entire data center building to find places of energy waste and ways to overcome these limitations.

There are several minor modifications and alternations which might be done and effect energy efficiency to a certain degree such as the use of T-5 lamps which consume less electricity. Also there needs to be appropriate motors for fans and cooling equipment which have variable speed. Just to give you a rough idea about what this small arrangement can do, a fan working at 80% of its full speed just consumes half of the electric power that it would have consumed if it had worked at full speed. Several other techniques exist which tend to increase efficiency such as placing servers in an appropriate manner, using low voltage transformers at the right points along the circuitry etc.

Blade servers are increasingly being used over conventional “U” servers which help to increase energy efficiency. Blades due to their configuration improved computation power for less energy consumed plus they require less space. Although it must also be kept in mind that blades are dense than convention servers due to their layout and can add to the cooling challenges of the data center.

There are other techniques that designers and end users are utilizing that include proper sealing of your data center perimeter to using blanking panels in racks. We would certainly welcome any suggestions or other tips you are using by providing your comments at the end of this article.
We should also point out the recent metrics to measure data center efficiency. These are the PUE and DCiE which stand for Power Usage Efficiency and Data Center Infrastructure Efficiency Ratio respectively. The former is the older parameter while the latter is a more recent one, though the both are closely related and DCiE is just the inverse of PUE. DCiE is the ratio of the energy consumed by the IT equipment of the data center, to the total power consumption of the facility. Different levels have been recognized for certifying data centers based on their DCiE value and the minimum value required for inclusion in the standards is 0.4.

Hence we see that today, the trend has been towards more energy efficient data centers despite the various challenges encountered during the process. World energy consumption in particular the data center sector is rising by the day, accompanied by a rise in the environment degradation. Current trends regarding energy conservation in the data center is encouraging for a better future in terms of energy availability, energy consumption and environment protection.


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