Microsoft said Thursday that it will delay the beta of its planned virtualization hypervisor for Windows, code-named Viridian, until the second half of 2007.
The Viridian beta originally was slated to be available for testing in the first half of the year.
The Viridian code is one of the most significant new features in the server as Microsoft's response to VMware, as well as to Linux competitors Red Hat and Novell, which integrated the open-source Xen hypervisor in their distributions.
Microsoft said the Viridian code will ship as an add-on 180 days after the next "Longhorn" Windows Server ships.
At this point, however, solution providers are skeptical that Longhorn will be shipping in volume this year. They predict that won't occur until 2008, which would stall Viridian's release until late 2008 or early 2009.
One industry source said there are no major "showstoppers" impacting the development of the server, but he noted that Longhorn has a complex SKU architecture and a dozen or so intended roles, which makes it more complex to build than the Windows Server 2003.
Integrating in Viridian will add to the complexity, he noted.
"Microsoft made a major error not buying VMware when they could have and then misreading the virtualization trend," said one partner familiar with the plans for Viridian. "As a result, Microsoft has not yet put a good equivalent into the market but is scrambling to adapt what it has and get what it needs out the door."
Microsoft is bumping into other scheduling problems with its current virtualization server, Virtual Server.
Virtual Server 2005 Service Pack 1, expected to be released by the end of March, is now delayed until the second quarter, though customers will have access to a release candidate at the end of April, Microsoft said. Beta 1 of the Service Pack was released last May.