Virtually large but apparently small

You've only got to hang around a datacentre for about 30 seconds before someone starts raving on about virtualisation. While the cost benefits of virtualisation are obvious, the management challenges often get swept under the carpet.

You've only got to hang around a datacentre for about 30 seconds before someone starts raving on about virtualisation. While the cost benefits of virtualisation are obvious, the management challenges often get swept under the carpet. But before we start worrying about that, here's a bigger picture question: just how much server virtualisation is going on in large enterprises?

The answer seems to be: not as much as you might think.

Speaking at Gartner's Infrastructure, Operations & Datacentre Summit in Sydney this week, analyst Phillip Sargeant said that while the benefits of virtualisation were widely recognised, actual implementations were not as common as you might deduce from the hype.

By Gartner's calculations, around 90 percent of the world's top 1,000 companies have some sort of virtualisation infrastructure in place for their PC server systems, with the vast majority coming from EMC's VMware division. "That sounds impressive, but the really interesting thing is that while they have a 90 percent share, you don't find that virtualisation is deployed right across the server farms," Sargeant noted.

"The penetration, even though they're in these companies, in the x86 world is very small. Only about six percent of the X86 servers that are installed have some form of virtualisation on them." In other words: everybody's trying it but nobody's crazy about it.

Virtualisation ticks all the right buttons — reduced costs, greener solutions, smaller datacentre footprints — so why the reluctance?

A big part of the reason, Sargeant suggested, is price. "It's very mature, it's very function rich but it's still seen by many organisations as very expensive," Sargeant said.

He also predicted that there would be a "need for price adjustments over the next couple of years," largely because of Microsoft's aggressive promotion of its own Windows Server 2008-based hypervisor product, Hyper-V.

In virtualisation terms, Microsoft is in the unusual position of playing David to VMware's Goliath (all that EMC cash notwithstanding).

Even though it plans to offer Hyper-V (currently in beta; Gartner is guessing at a late 2008 release) free with Windows Server 2008, it will take a while to catch up. "A lot of the virtualisation functions we see delivered from VMware today, Microsoft won't have for some time," Sargeant said.

One big challenge for Microsoft is making its hypervisor code more compact. (Blimey, there's a shock: Microsoft writing bloated code.)

Sargeant said that the core code for VMware's ESX Server is around 32MB in size, while the free Xen system is anywhere from 120MB to 256MB. By comparison, Hyper-V is between 1GB and 1.5GB in size.

That's not a problem for storage, but it is for stability — the more code you have, the more chance of it going wrong or interacting nastily with virtualised OSes. "They really need that to be very resilient and very reliable and available," Sargeant noted (a goal Microsoft could apply to all its software, by the way).

That said, he isn't betting against Ballmer and the boys. "The two juggernauts will be VMware and Microsoft," Sargeant said. "VMware is going to control for some time the enterprise space; Microsoft is going to control the SMB space."

By 2009, Gartner sees the penetration of virtualisation rising to 11 percent. That's almost double today's numbers, but it doesn't seem that we'll be throwing out those stand-alone servers quite as soon as we thought.