Like a lot of its peers, the IT department at Alameda County Medical Center (ACMC) got its feet wet with virtualization several years ago, using VMware ESX for server consolidation. But these days, ACMC opts for Citrix XenServer over VMware wherever possible.
XenServer has the performance and features the Oakland, Calif., hospital needs, at a fraction of the cost of VMware Infrastructure, said Dave Bennett, ACMC's director of technology support. "I have a hard time spending our hard-fought dollars if I don't have to."
Bennett said the features his staff came to rely on with VMware are all in XenServer, including live migration (XenMotion), the ability to run both Windows and Linux applications, and for physical-to-virtual migration. "So far, all the functionality we use day to day is there," he said.But from a cost perspective, the XenServer licenses cost Alameda County quite a bit less than VMware ESX. "For XenServer Platinum, I paid just a little bit more than just the yearly maintenance on VI3 [ VMware Infrastructure 3] licenses," Bennett said. Bennett declined to cite specific numbers, but according to VMware's website, one year of Gold (12x5) support for a dual-processor VI3 Enterprise Edition license is $1,208, and Platinum (24x7) support is $1,438. Citrix has VMware looking over its shoulder
Bennett also prefers some features of Citrix XenServer over VMware. When Alameda staff members began using VMware ESX, for example, they were told to configure VMware's VirtualCenter (now vCenter) management console on a standalone server, without clustering.
"That bothered me, because it was a single point of failure," Bennett said. Unfortunately, when the hospital experienced a total power failure at its data center, that design flaw came back to haunt ACMC. Because the VirtualCenter host had crashed unceremoniously, Bennett and his staff had trouble getting it back up, delaying the restart of the five ESX hosts that it managed.
XenServer uses a different architecture for its management tool, XenCenter. Rather than store all configuration in a central location, Citrix puts a copy of the management console on each XenServer host, so there's no one point of failure, Bennett explained.ACMC's particular problem with VirtualCenter can be avoided by setting it up in a failover configuration, said Gary Chen, the research manager for enterprise virtualization software at Framingham, Mass.-based IDC. But on the whole, Bennett's point is well taken: Technically, in Chen's view, VMware has few advantages over Citrix XenServer anymore. "Citrix is catching up; all the competitors are," Chen said, and are pricing their wares very competitively. Therefore, organizations like ACMC aren't unusual anymore. "The market used to be dominated by VMware, but as competitors offer things that can legitimately compete with it, people are increasingly looking at VMware alternatives." Nonetheless, VMware retains a distinct lead in some areas, Chen said. Bennett's preference for XenCenter over vCenter notwithstanding, "it's still easier and faster to do everyday things like migration or taking snapshots in vCenter than in XenCenter," Chen said. And as far as the hypervisor is concerned, "VMware still has a slight performance advantage, particularly when it comes to I/O." VMware still flaunts bigger ecosystem
Furthermore, there are many intangibles that come with the market leader, Chen said, even if it is more expensive. For one thing, "skills are a lot easier to find," he said. Likewise, more third-party software tools support VMware than Citrix. "With the market leader, you do buy into a larger ecosystem, and that has value," Chen said. Echoing this idea, ACMC's Bennett acknowledged that the hospital probably won't become an all-Citrix shop. "I don't see VMware going away anytime soon," he said. That's because some ISVs [independent software vendors] will only support their applications running under VMware and not Citrix. "They've just been around for longer," Bennett said.