The Xen technology lets users run multiple operating systems as guest virtual machines on the same hardware, allowing for the better utilization of resources.
Novell baked Xen into its current SLES 10 (SUSE Linux Enterprise Server) product, which shipped in July. Red Hat, based in Raleigh, N.C., is including Xen in its upcoming RHEL 5 (Red Hat Enterprise Linux) release slated to ship late this year or early 2007.
"What makes us most nervous is putting a bad taste in someones mouth around the Xen technology, which we think is business-transforming. We should not screw this thing up and put a cloud around Xen," Stevens told eWEEK Aug. 16 in an interview.
"I would much rather a customer had a solid experience with Xen. I think they [Novell] are being cavalier. We know what we need to be enterprise-ready and we already have a checklist of everything we need for that. They [Novell] have decided its more important to be first. Thats fine and maybe makes sense for them," he said.
For his part, Novell CTO Jeff Jaffe told eWEEK in an interview at the LinuxWorld Conference & Expo in San Francisco that the company had done an enormous amount of testing and firmly believed the Xen technology was ready.
"Could it be that Red Hat is embarrassed about the fact that they are six months late? This is the most transparent ploy and contradicts their own press release in March where they said Xen was ready. Its totally a joke," he said.
But Stevens said his comments, and other comments from Red Hat executives on this issue, were not designed to attack Novell, but rather to be very open with those of Red Hats customers who, after hearing Novells comments that Xen was ready for use in the enterprise, questioned why Red Hat was not already delivering it.
When asked by eWEEK if he had run SLES 10 and seen its virtualization experience, Stevens said he had not, adding that all Red Hat needed to know were all of the issues that its team was currently fixing with the upstream XenSource code base, from data corruption to "everything else. Do we want to bring that out to the market? Absolutely not. We want to work and drive robustness," he said.
Asked if some of these problems could be related to integrating Xen into Red Hats operating system rather than Xen itself, Stevens said that was "absolutely not" the case. "The other stuff is pretty much done; all of the manager APIs, the installers, the console work is all done," he said.
"This is about getting SMP [symmetric multiprocessing] support to work, and we just redid a lot of the network transmission and we got about a 5x improvement," he said.
Red Hat is going to bring virtualization to millions of servers in a pervasive way, and that means ongoing hard work to meet the broad criteria of enterprise readiness, Stevens said.
Novells Jaffe agreed that creating virtualization technology "is not trivial" and is an open-source project that came out of XenSource. However, Jaffe said many of Novells engineers participated in the Xen project.
"There is a lot of industry momentum and support around the Xen technologies, from the chip manufacturers to the system-level vendors, the Linux distributors and even Microsoft, with its recently announced relationship with XenSource," he said.
Red Hats Stevens said that while Novells engineering team was doing great work, its management team had made a conscious decision to bring Xen out first "and maybe theres an opportunity there, but we dont want to be first, we want to be right," he said.