January 4, 2010

By Dave Trowbridge

A perfect storm is converging on data centers worldwide. Like any hurricane, it's driven by heat energy: in this case the waste heat from ever-denser racks of blade servers.  Every watt of IT power can require as much as 2.5 watts for cooling, and the combined business and environmental impact of the energy needed is driving interest in the green data center.

Electricity is already one of the top three costs for business, and the number one cost for data center-focused companies like eBay and Google. Executives worry that the soaring energy costs of increasingly powerful data centers could become a limiting factor for business operations or expansion. Meanwhile, according to a 2008 report by McKinsey & Company, carbon dioxide emissions related to data center energy use worldwide are already equivalent to those from the entire nation of Argentina, the world's 24th largest economy.

Getting more IT power per watt is critical to reducing energy cost and the environmental impact of data center operation. Fortunately, businesses are discovering that efficiency and the green data center are intimately linked; if you do the first right, you get the other.

Getting Started with a Green Data Center

Although data centers are complex environments, it's easy to get started on energy and cooling efficiency, says Douglas Alger, Cisco's IT architect for physical infrastructure and author of the new data center design book Grow a Greener Data Center from Cisco Press. "Creating a green data center involves more than just conserving energy, but that's where one finds the greatest impact, especially when retrofitting an existing space."

This needn't involve anything more than a close look at airflow in the data center. "A lot of opportunities involve little or nothing in the way of budget, but simply making sure that cold air is getting where it's needed," he says. "Sometimes it's as simple as checking to see that the right air outlets are open or closed." A tangled mass of network cables, an open space in a rack, an air leak where cabling exits through the ceiling or floor—all these can reduce cooling efficiency.

Other ways to go green with an existing data center include:

• Put timers and motion sensors on room lighting.
• Consider server processing power/watt or network equipment port density on new purchases.
• Consider "close-coupled cooling," so cool air is generated as close as possible to where hardware is generating heat
• Use virtualization technologies, which allow greater utilization of hardware resources to accomplish more. Fewer systems means less power and cooling will be needed.
• Implement data center energy management, which can reduce costs by as much as 20 percent

Moving Your Green Initiative to the Next Level

Moving beyond such incremental improvements requires both organizational and technological change. Whether it involves retrofitting an existing data center or building a new one, going green requires a fundamental shift in corporate governance.

Dean Nelson, senior director of global data center services at eBay, says this involves two things. "You need executive alignment from the CEO on down, and you need a leader: someone with both budget and operational authority who's passionate about the initiative and responsible for its success."

The best place to start selling a green data center is often the CFO's office, says Rob Aldrich, senior manager and principal for Cisco's efficiency assurance program. "Go to someone who sees the bills for both IT and power, and work out a split in the savings. Work it so IT gets to use half the savings to reduce its top line and the facilities group gets the other half off their bottom line. By doing this you can in turn finance a sustainable sustainability program."

The Technologies of Efficiency

To make the right technology choices, you need to know three things:

• Where you're starting (a baseline)
• What your savings will be (sound metrics), and
• What is the risk involved in making proposed changes.

A simple utilization audit is a good place to begin. Server utilization in the U.S. is only 10-20 percent, Aldrich says. "That means 80 out of 100 servers in your data center are doing very little productive work, using 'vampire power' and consuming cooling resources."

The correlation between utilization and energy efficiency makes data center virtualization a major part of any green initiative, with a very quick payoff.

High-density, processing-intensive systems run hot, so accurate temperature measurements are critical. This requires a highly granular sensor network to deliver rack-level awareness of how well your cooling strategies are working.

Automated Power Management

Once you know where you're starting and how well your strategies are paying off, automation can hand you a big win. An increasing number of devices support some form of automated power management, enabling unused equipment to be put in a low-power state and re-powered on demand. This allows IT to manage energy as a service, which gives a better view of productive work-per-watt and helps strengthen the business case for a green initiative. 

"Cisco EnergyWise, available on our entire Catalyst line, is a good example of this," says Aldrich. "We built it into Cisco Internet Operating System to give operators a scalpel for whittling away inefficiency where they only had a club before."

In some EnergyWise pilot deployments, Cisco has seen a 20 percent reduction in energy use. Cisco spent $135 million on power in 2008; rolling out EnergyWise worldwide is expected to save the company $27 million in the first full year of deployment.

Go Green with a New Data Center

Energy-management architectures like Cisco EnergyWise are a fundamental part of new data center design. Physical architecture is equally important, both in terms of the building and the layout of the network.

"Physical infrastructure often gets overlooked," says Alger, "but good design requires a holistic approach." The tendency (due to a lack of granular temperature measurements) is to think of a data center as a big, monolithic space, and computing resources as a kind of homogeneous mass, so that every rack gets the same power availability and cooling.

This doesn't make business sense, says Aldrich. "Why should a company want to put its print servers on the same level as far more critical application servers?" A flexible, modular design, both for devices and the physical space, lets data center operators prioritize power and cooling resources in terms of the business value delivered by various devices and subsystems.

"You want to be able to make any power and cooling changes needed to adapt to succeeding generations of IT equipment within the design life of the building itself," he notes.

Green 2.0—Rethinking the Data Center

Each of these experts has a different definition of Green 2.0, but all three agree that getting there will involve paying intense attention to every detail of data center design. This starts with the site decision, which involves details ranging from existing infrastructure to the local cost (and sources) of electricity to worker commute distance and everything in between.

Fundamental device design will have to change, as well. "We have to rethink everything, every design layer," says Nelson of eBay, who is also founder of Data Center Pulse, an industry group with more than 1,300 global data center operators in 55 counties. "For instance, I think water-cooled devices are inevitable as power densities continue to skyrocket. From my perspective, that will be game-changing for data centers and equipment vendors alike."

Green 2.0 will also require intense intra and inter-corporate collaboration. "One of the biggest mistakes a company can make is thinking it can solve data center design problems on its own," says Nelson. "The more eyes on it, the more peer conversations, the better the solution. You'll get a much larger benefit from sharing than any momentary competitive advantage gained by secrecy."

Alger agrees that collaboration helps spark unexpected solutions, and he's amazed by the creativity he's seen in his best-practice engagements. "For instance, data center waste heat is used to warm everything from warehouses to greenhouses, and even public swimming pools." (See the Sidebar for some examples from Alger's recent book.)

One thing is certain: This transition, as difficult as it may prove, cannot be avoided. As Aldrich points out, data center operators have always focused on availability, which made them risk-averse.

Now, he says, "they face a new risk: being dragged down competitively by the costs both for energy and of compliance with green regulations. A proactive stance is the only way through the storm."

Dave Trowbridge is a freelance writer based in Boulder Creek, CA