Energy Savings In The Data Center
ABSTRACT
Pros Offer Strategies For Successful Energy Management:
FULL DOCUMENT
The ongoing conversation about global warming and green industrial practices is increasing the emphasis on capturing energy savings in the data center. Data centers use a tremendous amount of energy, so no matter what side of the argument over global warming one chooses, the bottom line is that data center energy savings can deliver significant monetary savings.
And that is music to the ears of top management, who must control costs in today’s challenging economic environment. Thankfully, experts recommend many strategies—some of them very easy to implement—that data center administrators can use to achieve substantial energy savings.
Key Points
• Without measurement and monitoring, management of energy efficiencies is impossible.
• Simple techniques such as implementing hot aisle/cold aisle layouts and bundling cables can provide big savings.
• Replacing aging equipment may seem expensive at first but can save money in the long run by alleviating the costs of maintaining older equipment.
Measure, Measure, Measure
Without measuring, there is no way admins can assess where their data centers are in terms of energy usage. And without determining a baseline, it is impossible to ascertain the effectiveness of measures undertaken to deliver energy savings.
Enhancing efficiency within the data center means limiting the energy usage of nonproductive work, such as cooling, heating, lighting, and humidity controls, says David Matusow, architect for availability services consulting at Sungard Availability Services (http://www.availability.sungard.com). According to Matusow, because organizations faced with rising energy costs want to drive down expenses and increase margins, gaining greater visibility into the energy needs and costs of equipment is becoming commonplace. The key is to measure energy used for productive work, such as operating servers and storage equipment, and the energy used for nonproductive work, such as cooling, lights, heat, and humidity controls.
A way to introduce monitoring and measurement capabilities in the data center is to add intelligent inline meters, says Herman Chan, director of Raritan’s power management solutions unit (http://www.raritan.com). Chan says these devices front-end a basic rack power distribution unit and help administrators understand and maximize circuit utilization. Also, he adds, intelligent inline meters connected to environmental sensors provide insight into environmental conditions around the rack, so administrators can be alerted to hot spots and to over-cooling situations.
Emily Reyna, project manager for the Corporate Partnerships program at the Environmental Defense Fund (http://www.edf.org), says monitoring and benchmarking measures reveal how energy is used in the data center and provide the data needed to develop the business case for making investments in energy efficiency. Reyna suggests three ways administrators can achieve this.
First, says Reyna, an organization should calculate and monitor their PUE (power usage effectiveness). The PUE is the ratio of total energy used by the data center to the energy actually consumed by servers over time. Even though an ideal data center has a PUE of 1—all energy is used to power servers—in reality, most data centers have a PUE of 2 or higher, she adds. So, reality means servers use half the energy, with the rest used for infrastructure to keep the data center cool and manage power quality.
Reyna also recommends that administrators track server utilization so underutilized servers—and even servers that are not used at all—can be identified. Finally, she adds, improved monitoring for variables such as temperature and humidity can provide the data needed to fine-tune cooling efficiency programs.
Keep It On, Keep It Cool
Power and cooling in the data center go hand in hand. Servers need power to function but also need plenty of cooling so power dissipated as excess heat does not interfere with server functionality. So, energy savings can easily be captured by performing tasks that optimize power management and cooling.
Darren Bonawitz, principal owner of a Kansas City data center called 1102 GRAND (http://www.1102grand.com), says administrators should install blanking panels to prevent air mixing between hot and cold aisles, maintain proper under-floor static pressure, remove debris and congestion from the area under raised floors, replace older computer room air conditioners with newer and more energy-efficient models, and utilize low-power servers.
The Environmental Defense Fund’s Reyna says one other way administrators can optimize cooling is to block holes in raised floors created by the removal of floor tiles to run wiring or conduct maintenance. Reyna says these tiles are usually not replaced after the work is done, causing cold air to escape and reducing the efficiency of the cooling system. A solution is to cut small holes for cables and replace floor tiles to cover holes.
Reyna says another way to optimize cooling is to bundle under-floor cables so there isn’t a gaggle of tangled wires and cabling restricting airflow. Finally, administrators should avoid relying exclusively on ASHRAE’s recommended equipment temperature ranges (64 to 80 degrees Fahrenheit) and pay heed to the higher temperature ranges recommended by server manufacturers. This allows for warmer data centers that reduce cooling costs and allow additional servers to be added to the data center.
Retire Clunkers
Older equipment often packs a potent energy inefficiency punch. However, many data centers continue to hang on to outdated servers in the name of frugality, not realizing that any savings captured from postponing the replacement of an older server may be going out the window in energy costs.
Marc D’Agostino, data center consolidation lead at EMC Consulting (http://www.emc.com), says older equipment is simply not as energy-efficient as new equipment. In fact, he adds, older equipment may make it even more difficult to assess the inefficiency of the operating environment. Admins must determine data center utilization and energy consumption patterns so they can identify the older and less efficient equipment.
To serve as a guideline for data center efficiency, the Environmental Protection Agency announced the first Energy Star requirements for servers in May 2009. To earn Energy Star status, a server must include items such as efficient power supplies that generate less waste heat; have capabilities for measuring real-time power use, processor utilization, and air temperature; have advanced power management features; and include a power and performance data sheet for purchases that standardize key information on energy performance, features, and other capabilities. 
by Sixto Ortiz Jr.