The two properties, which weren't specified by Digital Realty in its announcement, are 2045 and 2055 LaFayette St. in Santa Clara. In a related deal, Microsoft paid Savvis $190 million for the building's improvements and equipment, and for early termination of its service contract with Savvis.

Dan Golding, a senior analyst with Tier 1 Research, which tracks the datacenter industry, tells GlobeSt.com that everybody comes out ahead in this deal. Microsoft, which was the sole tenant of the premises, saves money by operating its own facilities and leasing directly from Digital Realty rather than a third-party provider such as Savvis. Savvis, meanwhile, gets $190 million of cash to go out and buy additional datacenters--likely in partnership with Digital Realty--that it can lease out to smaller clients that will order more of its services, which is how the company makes its money.

"Microsoft doesn't use Savvis services; this was a very-low-margin pass-through deal that was created during the bad times, after the telecom bust hit, when Savvis needed revenue and needed to fill up its datacenters," Golding says. "Now Savvis is doing very well and the margin on this [arrangement with Microsoft] is much less than anything else they are doing."