Practical Steps toward a Green Data Center

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Tuesday, 22 June 2010 11:03

Written by jeffrey clark

Energy efficiency and reduced power consumption in the data center are becoming less about simply reducing costs and more about improving environmental friendliness and about keeping government regulators at bay. As public awareness of environmental and energy issues grows (and as the political climate becomes increasingly hostile to industries—such as the data center segment—that are power hogs), companies must find ways to reduce their energy usage. Government regulators and increasing demand for energy are both contributing to increasing energy prices. In the face of ever-increasing demand for IT services, this is no small task, and making significant reductions in a data center’s energy demands can be extremely expensive. Nevertheless, reducing a data center’s energy consumption and its corresponding environmental impact need not break the bank—companies can take a number of simple and practical (and often inexpensive) steps in their data centers to achieve a better public image, reduced energy usage, greater efficiency, and reduced operating costs.

When taking steps to improve a data center’s energy efficiency and reduce its power consumption, companies must be careful to avoid falling into the trap of simply trying to reduce the data center’s power usage effectiveness (PUE). A Processor.com article (“Lower Your PUE”) emphasizes this point. The article notes that “PUE is a tool, and it can be manipulated.” For instance, in a 2009 article entitled “Data center efficiency and the limitations of PUE," Ian Bitterlin, Director of UPS Systems Division at Prism Power, notes that “[c]ooling systems powered by natural gas...can have a [PUE] below 1.2 because...the energy content of the natural-gas” is not included in the PUE calculation. Thus, simply reducing a data center’s PUE is not the same as improving its energy efficiency or even reducing its power consumption. Indeed, a data center could potentially become more inefficient and more of a power hog and still reduce its PUE.

Some of the broad steps that companies can take in making their data centers more energy efficient mirror overall trends in the industry. For instance, virtualization is becoming increasingly common for a number of reasons. Server virtualization (for instance) allows the data center to increase the utilization of fewer servers, thereby decreasing the overall needed infrastructure. Not only does virtualization save on equipment costs (such as server purchases), it decreases power consumption because fewer machines are required, and those machines do not sit idly for as large a portion of their operating time.

Often a tag-along with virtualization is consolidation—these two are not necessarily the same, however. Virtualization can increase server utilization, but if the data center doesn’t correspondingly reduce the amount of unnecessary equipment still drawing power, it will make little progress toward energy efficiency. The data center operator must also eliminate unnecessary equipment. This process may include equipment that is unneeded after a virtualization system is deployed, or it may mean, for example, elimination of unnecessary redundancy. As the Processor.com article points out, “[m]anagers often work under the constraint of needing five-nines of uptime reliability, but this is often impractical in the real world.” Thus, maintaining a realistic outlook on uptime and avoiding unnecessary redundancy can greatly improve efficiency.

Another important trend in data center efficiency is increased operating temperatures. Instead of always reducing temperatures in the data center, companies are beginning to increase temperatures (within reason, of course), in an effort to offset the tremendous cooling costs associated with the equipment. Use of outside air, especially in colder climates, is a way to reduce reliance on electricity as a way to cool equipment. Furthermore, improving the air-flow characteristics of the data center can also be a tremendous help. This need not involve complicated modeling or expensive refits—simply dividing the data center into hot- and cold-air zones that minimize mixing can greatly improve cooling efficiency.

Other simple steps that can increase a data center’s energy efficiency include simply turning off equipment that’s not in use and making sure that energy-efficiency features on equipment are not disabled. These features (which may involve, for example, putting a processor in a low-power state when it is idle) cannot improve a data center’s energy characteristics when they are disabled!

These few steps can be summarized in several key principles: don’t power equipment that’s not in use, increase resource utilization (virtualize), get rid of unneeded equipment (consolidate), and improve the data center’s cooling characteristics. To be sure, the last one is broad and can be as expensive as the company wants to make it. Nevertheless, several fairly simple and inexpensive steps can provide significant returns, both financial and otherwise.

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