The conventional wisdom is that VMware and Microsoft Hyper-V have run away with the virtualization market. But IT professionals who use commercial Xen-based virtualization options defend their choice on the basis of conserving precious IT budget as well as functionality.
Three years ago, after realizing it could not afford VMware, the city of Lenexa, Kansas, deployed XenServer when the technology was still owned by XenSource. "Even with a special government discount, the quote from VMware was $125,000," said Michael Lawrence, the city's CTO. "That would have eaten up my entire network budget in its entirety. We just couldn't do it -- period."
The city spent about $11,000 for eight XenServer Enterprise and four Standard licenses, and has upgraded to Citrix XenServer 5.5 with Essentials Enterprise Edition. According to Lawrence, the only substantive advantage that VMware claimed at the time -- the ability to run on servers without virtualization-enhanced processors -- is now moot, since all servers now ship with these processors by default.
The city runs XenServer on two six-server Hewlett-Packard BL495C Blade Centers, with one chassis in its production data center and another at a disaster recovery location. The city runs a standard set of back-office applications, such as file servers and Microsoft Exchange, with about four virtual machines (VMs) per blade. "We did run all the VMs on a single blade just to see that it could be done," Lawrence added.
Everything works fine, but Lawrence is most pleased about the price. The nearby city of Overland Park went with VMware three years ago, "and they're looking at our XenServer stuff and beating their heads against the wall; their maintenance contracts are more than we paid for the entire license," Lawrence said.
Nothing wrong with Novell SUSE Xen
The Colorado Department of Corrections is another happy Xen customer. It began virtualizing its servers last year without spending a penny. Facing a shortage of power to its data center, the Novell shop decided to take advantage of the Xen capabilities in Novell SUSE Linux. It has since converted 26 physical servers – about half its server farm -- to eight blade servers that run applications such as RIM's BlackBerry Enterprise Server. And it won't stop there.
"When we're done is when we've virtualized everything we can," said John Jubic, the end user solutions manager for the department.
Jubic said the department opted to go with Novell SUSE Xen based on the strong relationship with its Novell primary support engineer. "I don't think there was anything extremely special about it apart from the service I get from them," he said.
That, and the zero-dollar price tag. Under tight IT budget constraints, a $100,000 request for new hardware had been turned down just the year before. "Since we already owned SUSE, there was no cost at all to move to Xen," Jubic said.
As an added benefit, the IT department regained a test environment. Before, "we didn't have space to even bring in new hardware," Jubic said, much less test and develop new applications. "We really needed to have someplace to work."
Go forth and virtualize
Wary of making the wrong decision, first-time virtualization users sometimes shy away from offerings such as XenServer or Novell SUSE. Conservative by nature, many IT managers want to avoid vendor lock-in with a product that might not pan out in the long run.
But experts say that the risk of going with something other than VMware or Hyper-V is low. "Technically, they all hold their own," said Tony Iams, a senior analyst at Ideas International Inc. in Rye Brook, N. Y. They may not feature advanced features such as VMware's memory overcommit, but for day-to-day functions, they have live migration and they support shared storage – key enablers for server consolidation, he added.
"At this point, virtualization for consolidation has become a no-brainer," Iams said. "It's squarely within that mainstream segment."
Furthermore, the emergence of standards such as the Distributed Management Task Force's Open Virtualization Format makes the risk of choosing the wrong hypervisor very low, Iams said. "If you make the wrong choice, you can always move off later on." With that said, "For short-term issues of server consolidation, if the price is right, I haven't seen any [hypervisor offerings] that fall down."
Nor is Microsoft Hyper-V necessarily a better option, despite being bundled with Windows Server 2008 R2, said city of Lenexa's Lawrence.
Even though the "Microsoft marketing juggernaut will drive people to Hyper-V, it doesn't even begin to compare with XenServer," he said.
Let us know what you think about the story; email: Alex Barrett, News Director.
Dig Deeper on Citrix XenServer