Chill out: Five ways to cut back on data-center power consumption

Use of blanking plates in server racks and DC power are just two ways to reduce data center power consumption.

Cutting back on the amount of power a data center consumes isn't necessarily tricky, but it does require a holistic approach that considers the IT, cooling and power infrastructures. As Kfir Godrich, CTO for EYP Mission Critical Facilities, a data center consultancy, says: "If you are not looking at your data center from the utility input down to the chip, and then back to the power and cooling, you are missing the target." These five tips - some for the here and now and others for longer-term strategizing - will help you curb power use in the data center.

How storage and network gear can help reduce the data-center power requirements

1. Don't overlook the obvious.

Seal holes in the raised floor left by equipment that's been moved or uninstalled. Install blanking plates in empty portions of racks where network gear or servers ordinarily would go. Relocate perforated floor tiles from hot to cool aisles. Enable the energy-saving features of servers and computers. If possible, turn off the lights in the data center.

Such efforts can help offset rising utility rates, users say. Facing rising rates, "we replaced our old monitors with Dell Energy Smart LCDs; we turned on all the energy-saving technologies in the PCs that power down drives and put them in sleep mode; [we changed out] any printer that didn't support power-save functions," says Tim Sander, vice president of IT at Applied Systems, an insurance-agency management-systems company in University Park, Ill.

Carmine Iannace, IT director for The Brattle Group, an economic consulting firm in Cambridge, Mass., says he has done likewise. "We've used blanking plates in our empty racks to direct airflow. We move around servers to balance the cooling load in the data center. In addition, we keep an eye on the servers that are in development - if they are not in use, they get shut down." Iannace also uses the energy-saving features of desktops and laptops, plus he mandates that employees shut down their computers at the end of the workday to save electricity. Further, he turns out the lights in the data center when no one is working there.

Chilling out

2. Energy-spec your servers.

Pay attention to the type of IT equipment you buy because it consumes 50% of the power used by the data center, according to a recent U.S. Environmental Protection Agency efficiency report. Focus especially on x86-based industry-standard servers; they consume 33% of the entire data center power budget. For example, make sure your systems vendors are not "over-spec-ing" power supplies or using high-wattage fans unnecessarily, says Colette LaForce, vice president of marketing for Rackable Systems, an x86 server maker. She recommends looking at systems that have at least 90%-efficient power supplies, which conserve more power and waste less heat than less-efficient models.

At Brattle, Iannace has outfitted all servers to run off of 208-volt power instead of 120 volt, so the power supplies within the servers are more energy efficient. He also upgraded the core Cisco network switch to 208-volt power. In addition, Iannace has incorporated multicore servers and consolidated through virtualization. The result has been a 50% reduction in cooling requirements, he says.

3. Consolidate and virtualize.

Tyler Kilian, supervisor of network systems for UniSource Energy in Tucson, Ariz., also points out the benefits of consolidation and virtualization. With physical servers, "we started running into constraints across the board - both in power and cooling," he says. "We are now at 80% utilization of our power infrastructure through virtualization - best practices for the industry say we are full at 80%. We've been able to maintain that 80% for the past several years even though we've increased our server resources dramatically."

4. Take DC power to the rack and back.

Reprovisioning a data center with DC power takes long-term planning. "You can add DC power to the rack instead of having separate AC power inside each server," Rackable Systems' LaForce says. "DC supplies are far more powerful, efficient and have far fewer parts in them, making them less failure prone. Putting them in the system and then bringing DC power to the rack can save 10% to 30% immediately" in your power costs. Most server manufacturers offer a DC power option.

5. Modify cooling and power systems

Another way to reduce power consumption in the data center is to re-engineer the chilling system. That would involve installing chillers with variable-speed fans, running chillers at higher-than-normal temperatures and using free cooling where available.

Advice from a cooling expert

"We are looking at having a more managed cooling and energy infrastructure - things we can track more specifically," UniSource Energy's Kilian says. "We are changing our cooling strategy to in-row systems that . . . will be able to adjust for the proper amount of cooling in the row. In areas with lower server densities, we will be able to turn the fans down to consume less power and [vice versa]."

Adjusting chillers to run at higher temperatures also can save money, EYP's Godrich says. "If you can run a chiller at 10% higher, you won't see any delta peak for your servers."

Godrich also says IT should take advantage of geography. Colder climates, for example, could provide a cost advantage in that cooling down air conditioners with ambient cool air or ice might be possible.

Connor is principal analyst for Storage Strategies Now. She can be reached at

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