As virtualsation technology gets increasing attention from large enterprises, the founder of the Xen open source project said recently that Xen will develop more quickly compared with competitors, including Microsoft and VMware.
“Microsoft [is] very much in catch-up,” says Ian Pratt, chief science officer for XenSource and professor at the University of Cambridge’s Computer Laboratory.
Speaking on the sidelines of LinuxWorld in London, Pratt said, “Xen has the advantage that there’s a large development community who are all highly motivated to make Xen look good. That means that Xen does move really fast. Anything new that happens gets done on Xen first.”
Pratt started the Xen project with his Cambridge University students four years ago. High interest in the project spawned a business, XenSource, which has created a virtualisation product, XenEnterprise, based on open source code.
By 2009, research company Gartner predicts, three technologies will dominate virtualisation: VMware’s ESX Server, Xen, and Microsoft’s Viridian hypervisor.
Xen has earned strong acceptance with vendors. Sun Microsystems is integrating Xen into Solaris 10. Xen is in Novell’s recently released Suse Linux Enterprise Server 10 and will be in Red Hat’s forthcoming Enterprise Linux 5.
Virtualisation involves running multiple instances of an operating system on the same piece of hardware, such as a server. Studies show servers often run at 10% or less of their capacity, a figure that has declined as CPUs (central processing units) have become more powerful. Using virtualisation can reduce the amount of hardware in datacentres, lowering energy costs.
While virtualisation has become a hot buzzword, only about 6% of x86 servers are using the technology, according to a study by TWP Research released in February. But Pratt predicts the figure will reach 100%.
Vendors continue to jump on the bandwagon. Microsoft’s Viridian hypervisor, which the company is incorporating into its Longhorn server, has an “architecture heavily inspired by Xen design”, Pratt says, meaning it’s a high-performance hypervisor with a small-code footprint.
Hypervisor technology manages hardware resources to allow multiple operating systems to run in isolation on the same hardware. The final version of Viridian is due about six months after the release of Microsoft’s Windows Longhorn server.
While they are competitors, Microsoft and XenSource agreed in July to make the next version of Windows Server compatible with Xen-based guest operating systems. Microsoft also agreed to offer technical support for instances of Windows running as a guest on XenSource’s XenEnterprise.
One of the next targets for the Xen project is developing what’s called “para-virtualisation” — refining the interface between the hypervisor and the operating system and how it uses resources of the underlying hardware, Pratt says.
The advantage is better performance.
“It’s much better to tell an operating system you have 256MB of memory rather than telling it that it has got 512MB and trying to fake out the extra 256 [MB] and swapping things to and from disks,” Pratt says.