Enterprise virtualization options have broadened with the open source vendor XenSource announcing it will take on the big guns with its own commercial software to run Windows and Linux guest operating systems.

This week XenSource, the company behind the open source Xen virtualization engine, announced its XenEnteprise software suite will support both Windows and Linux guest operating systems, paving the way for a third player in the commodity virtualization space alongside VMWare and Microsoft.

John Glendenning, XenSource's VP of worldwide sales, said the ability to run unmodified versions of Windows on Xen means the company can now offer the "same performance and 80 percent of the functionality at 20 percent of the cost" as the market leader VMWare.

Glendenning said because processor manufacturers were developing virtualization capabilities in parallel with the Linux-based Xen hypervisor, the Windows virtualization capabilities "matched the support" of existing solutions.

"We already have a short-term roadmap to close the gap with live migration built in and a commercialized, hardened, enterprise-grade product," he said, adding the company works with channel partners for support and sells software licences for revenue.

The XenEnterprise package includes additional functionality over the open source product including a management console, high-availability capability, and storage services support.

Glendenning said in addition to being the first endorsement of open source in the enterprise, Microsoft's partnership with XenSource involves collaborate development which will result in full support for Longhorn server when released next year.

"The most significant thing about this week's announcement is the market now has a choice which it hasn't had before," he said. "From a customer and channel partner perspective having an option is important. Our job is make sure Xen enterprise delivers the best virtualization in the market."

XenSource will announce its ISV program this month where a number of "big name" software developers can add functionality to Xen to rival other offerings.

Xen users include the high-profile Amazon e-commerce site and Sydney-based fashion design and direct sales company UnderCoverWear.

"It's difficult to count the number of users. The tech has been the market for four years and is well deployed," Gelndenning said. "It's important for the enterprise to understand it's well deployed and is integrated into Intel and AMD [architectures]."

A confident Glendenning said within a short time, beginning next quarter, the functionality of Xen will be up to 95 percent of VMWare and include better high-availability support, including live migration.

Locally, IT distributor Express Data is working with XenSource to provide pre-sales support to partners.

XenSource also has a pilot program to allow prospective customers to go beyond the proof-of-concept stage and test the software.