While VMware pretty much created the virtual machine market on x86 servers and has enjoyed a nearly uncontested leadership position, enterprise customers this year will find a wider variety of options for virtualising servers, operating systems and applications.

Vendors such as Microsoft and SWsoft and the open source virtualisation project Xen are offering alternatives to VMware as interest in the technology grows. In addition, start-up companies, such as Qlusters and Akimbi Systems, are attacking other areas of virtualisation with tools to create high-availability clusters or to enhance applications running on top of virtualised environments.

As x86 processors become increasingly powerful, customers are looking for ways to get more out of the low-cost, standards-based platforms they have, analysts say. Virtual machine technology, which creates isolated software containers that include an operating system and applications, is one way to do that.

Interest in virtual machine technology has been growing. IDC says the market reached more than $300 million in 2004 and is on pace to grow at a rate of about 18 per cent over the next few years.

"It's been one of the faster growing technologies that we've encountered," says Galen Schreck, a senior analyst at Forrester Research. "It quickly went from 'You want me to do what?' to 'Hey, that sounds like a really good idea.' The people I speak with at this point are convinced of the technology and convinced of the solidity of the idea."

The growing interest is resulting in a surge in the number of companies rolling out virtualisation technologies, says Dan Kusnetzky, a vice president at IDC.

"Expect to see some interesting twists on [virtual machine] technology," he says. "Right now, you could think of this technology as starting at the hardware and looking up - how you encapsulate the operating system and all the software above it. That's not the only way of thinking about it."

Akimbi is building an enterprise application that will leverage virtualisation platforms. According to the company's Web site, it appears the product would include management tools that interface with VMware, Microsoft Virtual Server and Solaris partitions.

"We're solving a business problem and it just so happens that we can use virtualisation technology as part of our toolkit," says James Phillips, Akimbi president and CEO. "We're really solving business problems by building applications that make clever use of virtualisation technology because it's available and it's affordable and it works."

Enterprise users can expect a product from Akimbi, which recently got funding from Hummer Winblad Venture Partners, Partech International and Stanford University, by year-end, he says.

Meanwhile, Xensource, a company founded to provide support and maintenance for the open source Xen virtualisation technology, also recently received funding when Sevin Rosen and Kleiner-Perkins added $6 million to the organization's coffers.

"Open source and virtualisation marry two fairly powerful trends and Xen is a tour-de-force piece of technology," says Nick Sturiale, general partner for Sevin Rosen.

Heavy mob wades in
IBM, HP, Intel and Red Hat are among those working with Xen to improve the open source virtual machine technology.

Rolf Neugebauer, a researcher at Intel Research Cambridge, says the chipmaker has been involved in the Xen project for more than two years. One of the focuses of Intel's work with Xen is to enhance security around the Xen virtual machines, he says.

"Our aim is to support multi-level secure systems, and we plan to extend Xen in a similar way as" Security-Enhanced Linux," Neugebauer says. SELinux is a project backed by the National Security Agency that adds access controls to the Linux kernel.

Xen takes a similar approach to VMware, but analysts say it has a ways to go before it will be a serious contender when it comes to enterprise virtualisation. One main hurdle is that Xen requires a modification to the Linux kernel. XenSource CEO Nick Gault says his organisation is talking with Red Hat and Novell, which have shown interest in incorporating Xen virtualisation into their distributions. However, analysts suspect it will be many months before the commercial distributions include the Xen technology.

"Of course, companies want to keep their eye on technologies that are on the horizon, but realistically open source virtual machines are not something that the average enterprise should be spending a whole lot of time on in 2005," says Gordon Haff, an analyst at Illuminata. "Strictly speaking in the x86 space for the highest end, most efficient, native virtualisation, VMware ESX server continues to be the only game in town."

Not that companies such as Microsoft and SWsoft should be discounted. Microsoft recently began shipping Virtual Server 2005, technology the company acquired with its purchase of Connectix in 2003. Virtual Server effectively divvies up the hardware so that multiple virtual machines can run on a single CPU. It's most similar to VMware's lightweight GSX server.

Analysts expect Microsoft to enhance Virtual Server, but say that VMware -- which already has rolled out management tools such as Virtual Center to streamline provisioning and configuration and VMotion, which lets users move live virtual machines from one physical server to another -- is far ahead of the game.

SWsoft takes a different approach to virtualising servers. It virtualises the operating system so that multiple instances of the operating system can be created from one installed version.

"There are advantages and disadvantages with each approach [to virtualising servers]. There's no one best way. If you provide virtualisation like SWsoft, you may or may not be able to run more than one operating system on that server," says Scott Donahue, vice president of Tier One Research. "But SWsoft can create a lot of different virtual servers using one host [operating system] and the cost savings are greater because you are only licensing one [operating system] per server rather than multiple [operating systems] per server."

That's what attracted Justin Schumacher, software and systems design engineer for industrial sensor product company Adaptive Instruments in Hudson, Mass., to SWsoft.

"We found with Xen and VMware that it did help isolate your software from your hardware and helped it make it a little easier to manage, but they didn't help the cost of hardware or software," he says.

Schumacher is testing SWsoft's Virtuozzo product and plans to put it in production when the Windows version is available in the first half of the year. Today, Virtuozzo is supported only in Linux environments.

"To use Microsoft Virtual Server, you have to buy one copy of Windows for the host machine and one copy of Windows for each virtual machine. You don't save a lot on hardware costs because you still need to pre-allocate RAM to each virtual machine, whether the virtual machine is using it or not," Schumacher says. "With SWsoft you only have to buy one copy of Windows, each virtual machine is using that copy. You also save hardware costs because RAM doesn't need to be pre-allocated."

For enterprise users faced with a growing number of virtualisation options, the most important task is to understand exactly how they want to benefit from the technology, experts say.

"Before they rush into this, I urge them to consider what are they really trying to accomplish, what the other ways to accomplish it might be," IDC's Kusnetzky says. "It's very important to look at vendors and what they're presenting as their road map. Virtual machine technology is just one of a number of technologies that can help create a virtual environment."

Find your next job with techworld jobs