Digital Realty designs, builds and manages large data centers for third parties, including collocation providers and hosting companies. It is one of the biggest providers of such services worldwide.

The company hired Manos last April as senior vice president of technical services, where he oversaw design, construction and technical operations for Digital Realty's data centers worldwide. Before that, he ran Microsoft's Data Center Services division.

Manos said via e-mail that he planned to announce his next move on Sunday. "The next chapter of my career brings me back in closer alignment with what I did for Microsoft," he wrote.

"I remain firm in my endorsement of Digital Realty Trust and hope that my involvement has helped to move the company forward," he was quoted as saying in a from Digital Realty.

Digital Realty said, "We understand that this was a difficult, personal decision for him and we wish him the very best in his future endeavors."