Manos has been leading Microsoft's efforts to build a global network of data centers to support its online services. He has been a champion of containerized data centers, which place servers and storage gear in shipping containers to achieve highly energy-efficient designs.

Manos will be senior vice president of technical services at Digital Realty, which designs and manages data centers for third parties. He will oversee the design and construction of Digital Realty's data centers worldwide, and lead a new professional services offering that the company plans to unveil shortly, it said in a Wednesday.

Manos will start at Digital Realty in early May, a spokesman said. Microsoft could not immediately be reached for comment.

Manos is the second prominent member of Microsoft's data center team to leave recently. In December James Hamilton, another respected data center engineer, left Microsoft to join Amazon Web Services.

Microsoft has been slowing its data center expansion amid the recession. Last October it said it would reduce data center capital expenditures by $300 million, and in February it it would postpone the construction of a data center in Iowa, and delay the opening of two others in Chicago and Dublin.