February 29, 2012, 9:33 AM — Online auction site eBay has slashed costs and maximised energy efficiency at its enormous new Arizona data centre, after employing best practices from The Green Grid.
Temperatures in Phoenix, Arizona - one of the most arid places in the US - regularly exceed 46C (115F). That is a far cry from the typical cool-weather locations that companies usually choose to build data centres, in order to reduce the need for power-hungry chillers.
However, by using the Green Grid's Power Usage Effectiveness (PUE) metric and Data Centre Maturity Model (DCMM) to guide the design and construction process, eBay's facility was able to achieve a PUE rating of 1.046 in some parts of the data centre, and a site average of 1.35. (PUE is the ratio of total facility power usage to that used by IT equipment.)
eBay decided to consolidate its data centre facilities in 2010, in the face of growing demand for data centre space due to the increasing number of registered users and listed items. The consolidation project, dubbed 'Project Mercury', aimed to combine 11 data centres into three, in order to achieve cost savings, decrease network latency and enable quick expansion with minimal impact.
The company's selected contractors in Arizona came up with a design for a six-megawatt facility that could be upgraded to 12 megawatts by adding two-megawatt containers on the roof. One container holding 1,500 servers can be lifted from the truck to the rooftop in 22 minutes.
To speed up deployment of new server racks, eBay has worked with vendors on a concept called "rack and roll," whereby it orders racks to specification. The vendor fills the rack with servers, does all of the cabling, labelling and loading of the OS. Then it delivers the rack to eBay, which can have it configured with its own applications within four hours.
The Green Grid claims that the modular, scalable design - both in terms of rack-at-a-time and container-at-a-time deployments - is ready to handle up to five generations of future technologies and provides a data centre space that halves the cost of hosting 80% of eBay's applications. eBay relied on total cost of ownership (TCO) to assess the total lifetime kilowatt hours (kWh) used by its servers while running the company's workload.
eBay's facility is also capable of free cooling year round in Phoenix, despite the sweltering desert heat, thanks to an oversized cooling tower that runs a condenser water loop system underneath the floor. Water is run through a heat exchanger, guaranteeing a maximum water temperature of 31C all year without using chillers. Server manufacturers have tuned their equipment to align with this goal.