Monday, November 23, 2009

Data center power

A recent study by Lawrence Berkeley National Lab, Self-benchmarking Guide for Data Center Energy Performance, revealed that in a typical data center installation, an average of 33 percent of total power goes to IT equipment. The rest is consumed by cooling (50%), the power system (9%), and lighting (8%). The most efficient data centers can achieve 80% power utilization for IT equipment. This measurement, however, does not take into account the efficiency of the computer systems at doing the desired work; only the ratio of electric power for computers vs. power for support equipment.

The real goal is to do the same or more electronic work using less power. Many data centers have expanded to the point where there just isn’t enough power or cooling to allow new projects. Expanding data center power and cooling infrastructure can be very costly, and will only result in increased annual costs. Spending the money to make the center more efficient solves the same problem and reduces expenses while setting the data center on the GreenIT path.

The simplest and most direct way to reduce power consumption in a data center is to reduce the power used by the equipment. In the average data center, for every watt reduced on direct electronic equipment (computers, network equipment, and storage), at least one more watt will be saved on the facility side (HVA/C , UPS, power distribution). Further, in the average data center this equipment is already at or near capacity. Therefore the most direct path to savings is in reducing the IT equipment power needs with such methods as consolidation, virtualization, use of larger disks in storage systems, etc. Efforts spend on infrastructure without corresponding IT effort is wasted, as any savings will eventually be re-absorbed by continued wasteful IT side growth.

Successful efforts must include both Facility and IT systems. This is the crux of the problem as these two groups generally have little to do with each other with very different goals and needs. Facilities often has the electric costs and infrastructure maintenance costs, with goals like reduce electric bill, maintain data center temperature and power. IT usually doesn’t have the electric costs for the computers it maintains, and has goals such as maintain up time, reduce equipment and IT maintenance costs. None of these goals are in opposition but the two groups do not likely talk to each other and many of their terms sound like a different language to each other.

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