How eBay Built Its New Energy Efficient Data Center

With more than 100 million eBay users buying and selling $2,000 worth of goods every second, data centers are a big deal to the e-commerce company. And maintaining all that data requires plenty of energy: eBay's data centers consume more than half of all the power used by the company.

Power consumption has been a key issue, and a significant cost, for data center operators. The Environmental Protection Agency estimates that U.S. data centers' power bills totaled $4.5 billion in 2006 (PDF), and energy use has grown since then. 

 

With its newest data center, though, eBay is readying itself for even larger loads while consolidating the equipment it already has and using energy more efficiently, in part by taking advantage of free cooling.

The company developed its new Phoenix facility, dubbed Project Mercury, with guidance from The Green Grid on best practices for energy efficient and adaptable data centers. That guidance includes The Green Grid's Power Usage Effectiveness (PUE) metric, which measures how much energy coming into a data center is used to power computing instead of cooling, lighting or other equipment.

 

It’s typically used to benchmark performance and track improvements. But instead of using the metric to measure its efficiency after building the data center, eBay decided to make PUE -- along with the total cost of ownership, which includes the cost of the servers and the total cost of the energy they will use over their lifespan -- primary factors in its design and equipment decisions from the get-go.

When planning its Phoenix data center, eBay stated it wanted a facility with a PUE of 1.2 and used that goal to guide its decisions. (Lower numbers indicate higher effectiveness.) The company said that the data center had a site average PUE of 1.35 during one week in January, with a 1.26 PUE at its best. Partial PUEs around 1.04 have also been recorded.

 

That's noteworthy considering that the project consolidated 11 data centers into three locations while deploying tens of thousands of servers in a six-month period, following the completion of its "Project Topaz" data center in Utah in 2010. The consolidation enables eBay to get out of leased facilities and into ones that it owns, where it can control the efficiency. 

 

The data center is also using its environment to receive free, year-round cooling in the form of a hot-water cooling system that uses cooling-tower water to chill containers and racks in the center. While computers use only 57 percent of the power in the average U.S. data center, the air conditioning and other equipment gobbling the rest, computers use at least 78 percent -- and up to 95 percent -- of the power in eBay's Phoenix facility.

 

The inside of the center was also developed with changes in mind, with a modular and scalable design that can handle up to five generations of new technologies.

 

The Green Grid details specifics of the project in a case study, "Breaking New Ground on Data Center Efficiency."