The analyst company did a side by side comparison of VMware's vSphere 4, released in May, Citrix's XenServer 5.5, released in June, and Microsoft's , which is due to ship with its Windows Server OS upgrade in October.
Despite several improvements, Hyper-V will still lack three of the 27 features that Burton Group considers requirements for most enterprise applications running in production, Burton Group analyst Richard Jones said at VMworld Tuesday.
Burton Group compiled a list of criteria for running enterprise applications in a virtual environment, including features related to high availability, live migration, memory management, security, networking, storage, licensing and power management.
Just a few months ago, VMware was the that met all of Burton Group's must-have requirements. It to the list in July following its release of XenServer 5.5.
The analyst company admits that its list of features won't be required for all scenarios, but it sees them as a good general guide. It also noted that Microsoft has won some customers for its existing Hyper-V products, especially among smaller businesses and for departmental use.
The features it still lacks for the enterprise, according to Burton Group, are the ability to prioritize virtual machine restarts; support for a minimum of two virtual CPUs per guest operating system; and the lack of a fault-tolerant management server.
The first can be important because dependencies can exist between virtual machines, so companies may need to start them in a particular order, said Burton Group analyst Chris Wolf. The second translates to a lack of compute power: Microsoft supports more than two virtual CPUs with its newest OSes, but only two with Windows Server 2003, and one for all other operating systems, Wolf said.
On the third point, Microsoft's System Center Virtual Machine Manager can't run on a cluster of servers, Wolf said. "Microsoft will argue that you can put it in a virtual machine and fail the VM over [to another server], but that's not the point; it can't be made fault tolerant," he said.
Nevertheless, the upcoming Hyper-V release has some significant enhancements, including live migration of virtual machines; cluster shared volumes; support for third-party cluster file systems; hardware-assisted memory virtualization, and virtual storage hot-add, Jones said.
The company also does better than Citrix on the list of features Burton Group considers "preferred" but not required. Hyper-V will lack 14 of the 42 preferred features, while XenServer lacks 17 and VMware seven. The picture is similar for "optional" features.
Microsoft responded to the findings by highlighting customers that it says are using its product. “Our customers have their own scorecards, and Ingersoll Rand, Jackson Energy Authority, and the University of Miami have experienced success and cost savings through using our products,” the company said via email.
Burton Group found at least one "preferred" feature that both XenServer and Hyper-V have, but which VMware lacks: virtual storage disk compatibility. "VMware is proprietary; it doesn't support other hypervisors," Wolf said.
Burton Group presented its findings at a session entitled "Hypervisor Competitive Differences: What the Vendors Aren’t Telling You."
It's hard for customers to compare vendors' products using their data sheets because each tries to make its products look best, and sometimes the vendors say they have a certain feature even if it is poorly implemented, Jones said.
Even Glemmestad, an IT engineer with Norwegian agricultural supplier Felleskjopet, said Burton Group's assessment made sense to him. He'd read that the analyst firm considers XenServer production-ready but came to the session to find out on what basis.
His company mainly uses VMware, but it is considering XenServer to virtualize their XenApp servers, he said.