Despite the recent war of words that is raging over the open source hypervisor Xen, the fallout likely to befall...
the virtual machine monitor will be minimal.
Xen is a virtual machine monitor for x86-compatible computers that can securely execute multiple virtual machines, each running its own OS on a single physical system. Commercial Linux vendors Red Hat Inc. and Novell Inc. have bickered publicly recently over Xen, trading accusations that the other's strategy is flawed.
When Novell made the decision to "bake-in" Xen with SUSE Linux Enterprise 10 (SLES10) in July, Red Hat executives were quick to pile onto previous statements that made it clear they believed Novell was only pushing Xen out the door so it could be first to market.
Red Hat chief technology officer Brian Stevens was quoted as saying the move was "cavalier," and at the Red Hat Summit in Nashville, Red Hat senior vice president of worldwide marketing and general manager, products division, Tim Yeaton said Xen would not be included in Red Hat Linux until it was "bulletproof."
The two sides have been polar opposites on whether or not Xen is ready for enterprise use. While both Red Hat and Novell have praised Xen for its strong application in the virtualization space, Red Hat has held off on including it in Red Hat Enterprise Linux (RHEL) until a later date while Novell has gone ahead and put Xen into SUSE Linux Enterprise Server 10.
Xen, as an open source virtual machine monitor for x86, enables the execution of multiple guest operating systems on a single server using a technique called paravirtualization.
Tony Iams, a senior analyst with Rye Brook, N.Y.-based IDEAS International Inc., said that the end users who have deployed or are testing Xen has little to worry about from sniping vendors, but they should remain wary of Xen's relatively young status in the virtualization space.
"I see this as just part of the standard competitive posturing between two companies," Iams said. "Red Hat will have it in RHEL5, but Novell shipped it now [with SLES10], and they made it out the gate first."
Having said that, Iams added that the stakes are still high in the race to optimize Xen-enabled Linux. "Once you establish a footprint [as Novell has] with the hypervisor – a critical layer of the stack – it tends to be very hard to dislodge you."
On the other hand, Iams said, even though Novell has included Xen, users should be mindful of the concerns raised by Red Hat. "Xen is a new technology and is not yet mature, and users need to be cautious of that as they should be with all technology," he said.
Iams added that users should understand what Xen-enabled Linux operating systems are and are not capable of doing: "What Novell has now is really only capable of hosting SLES10 workloads on top of SLES10. If you want to do anything else, like with older versions of SLES or other Linux distributions or even Windows, you're on your own."
Other experts, like Gordon Haff, senior analyst with Nashua, N.H.-based Illuminata Inc., have argued that support from big name vendors like IBM and Novell could give Xen an undeserved black eye by pushing it too hard before it is ready for the enterprise.
The sentiments of several end users contacted by SearchOpenSource.com for their thoughts on Xen and virtualization reaffirmed analysts' caution.
Timothy Happychuk, the director of IT for Winnipeg-based Quebecor Inc., had deployed VMware's ESX Server with much success but remains hesitant to apply Xen to his data center.
"With Xen we just can't live with the unreliability in an enterprise environment, but maybe in a laboratory," Happychuk said. "The behavior [of Xen] was a huge red flag for us, because if you cannot quickly explain what's going on with a system and then not explain that to your users, then that's not a technology that is ready for prime time."
In light of any uncertainty, Iams recommended IT managers today use Xen in usage cases that involve testing and development.