Over the course of a year, the engineers at Nissan's vehicle manufacturing plants in Smyrna and Decherd, Tenn., have implemented virtualization to consolidate 159 servers used in assembly and component manufacturing down to 28.

The consolidation is impressive, not only for its scale, but for the fact that it's been carried out by manufacturing and quality-assurance specialists outside the regular Nissan IT department. None of the servers involved was considered part of the business information services function, said Phil D'Antonio, department manager over conveyors and controls engineering in Nissan's Smyrna plant.

The consolidation was accomplished in some cases by combining what had been standalone but related manufacturing applications into one application, which was then run in one Microsoft Hyper-V virtual machine. That is, the server reduction reflects manufacturing applications being combined as well as stacking up virtual machines per server.

In Smyrna, Nissan is running an average of eight virtual machines per Dell R900 rack server; in Decherd, it's averaging six. Many pieces of the software infrastructure, such as the database, Active Directory, and Web servers, did not lend themselves to being virtualized and remain standalone applications, said D'Antonio.

The consolidation has led to a 34% savings in computer electricity consumption at the Smyrna plant, where preliminary measures have been made. "At Nissan, we're a [U.S. Department of Energy] Energy Star partner. It's very important to us to us to conserve energy and protect the environment," D'Antonio said.

In addition, what had been three computer rooms at each location has now been reduced to two. Two will be maintained, no matter how much consolidation occurs, so that a mishap that knocked out one computer room wouldn't shut down the plant. Each room can serve as a recovery facility for the other, for the servers at another plant. Virtualization makes that process simpler and easier to maintain, said D'Antonio.

The Hyper-V virtual machines are running manufacturing, quality-control, and process engineering applications, such as paint mixing for different models. The Smyrna plant produces Altima sedans, coupes, and hybrids; Frontier pickups; Maxima sedans; and Xterra and Pathfinder SUVs. The Decherd plant produces engines, crankshafts, and cylinder blocks.