Xen making gains in cloud computing, but where's the Zen?

Xen has yet to reach Zen.

Xen's open-source standard for virtualization is gaining traction as cloud computing takes off, but despite claims by some companies that their Xen hypervisors outperform others, Simon Crosby, chief technology officer of Citrix, which acquired XenSource, had this advice during his keynote speech at LinuxWorld on Thursday: don't believe it.

"To say my Xen is better than your Xen is utter nonsense," Crosby quipped.

But while Xen, like its other virtualization offerings from VMware and Microsoft, are designed to allow a computers to operate multiple operating systems simultaneously to shift work demands among servers in an adaptable data center, the technology, while important, remains in flux.

Crosby's Xen evangelism comes as the industry faces growing competition from the likes of Red Hat and others that have begun touting KVM over Xen as their virtualization software.

And even within Xen, some competition exists, given its base bits change, resulting in different features depending upon when a snapshot was taken and built into a product. And another differentiator comes from the management tools that take advantage of the virtualization, such as tools that create new virtual machines to ones that monitor the machines if they become overburdened.

Despite competition from other forms of virtualization software, Crosby finds the use of Xen is growing. The Yankee Group, for example, estimates that 17 percent of the enterprise server market uses Xen, but Crosby estimates it may be more.

Xen, for example, is finding its way into laptops, as it addresses legacy workload issues, Crosby noted.

"Xen is everywhere in the clouds that I visit," said Crosby.

Xen has a development community to rally behind the virtualization technology and drive improvements and its integration into a range of products, other than just servers.

Nonetheless, challenges remain for Xen, such as virtual machines still tend to be tied to a specific hypervisor vendor and version, in addition, the technology is not verifiably secure.

Noted Crosby: "hypervisors are free...the next challenge is getting them ubiquitous."