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The town of Oakville, Ont. recently replaced 10 computer servers with three. The municipality located just west of Toronto used Virtual Server software to transfer programs from separate, small servers to a cluster of three machines. Virtual Server, from Microsoft, works by fooling each application into thinking it still has a machine to itself. The move saved money, not just by eliminating computers but by reducing maintenance and support costs, says Jeff Lanaus, Oakville's acting director of information systems and solutions.

Publisher Quebecor Inc. replaced 72 separate machines with just two 16-processor International Business Machines Corp. servers running virtualization software from VMWare Inc. of Palo Alto, Calif. Replacing assorted hardware with two identical machines greatly simplifies maintenance and support, says Tim Happychuk, Quebecor's western region IT director and architect of its virtualization project. The city of Stratford, Ont., bought one $15,000 machine running Virtual Server to do the work of four aging servers that would have cost about $8,000 each to replace, says Ron Roy, Stratford's manager of information technology services. It's becoming apparent that virtualizing servers is becoming more common. A survey by research firm International Data Corp. last year found about 22 per cent of servers were virtualized, but that figure was expected to double within 12 months, says Matt Eastwood, vice-president of enterprise server research at the Framingham, Mass., research firm.

The main reason is cost.

“Companies are looking for more ways to basically stretch their IT budgets,” says Hilary Wittman, product manager for Windows server at Microsoft Canada Co. in Mississauga, Ont. The number of servers in use is growing at around 6 million a year, Eastwood says, and the cost of the hardware is only one small part of the equation. The power consumption of these proliferating servers is one of the biggest concerns driving virtualization, says John Bora, vice-president of marketing at XenSource Inc., a Palo Alto, Calif., firm that distributes open-source Xen virtualization software; the company recently launched a commercial version called Xen Enterprise. Space and maintenance costs are other factors.

Companies typically install one server to run one software application because systems running multiple programs can't always ensure that each gets the resources it needs, and because one failed program can crash the entire machine, says Raghu Raghuram, vice-president of platform products at VMWare. As a result, Eastwood says, it's common for servers to use only around 10 per cent of their capacity.

Virtualization divides one physical server into two or more “virtual machines” that operate as if they were independent, eliminating problems such as resource conflicts or the failure of one application putting others out of commission. It's as if, instead of several people sharing a house and trying to work out when each one gets to use the shower, they divided the building into separate apartments — with soundproof walls.

Nobody aims to push servers to 100-per-cent utilization — that would leave too little allowance for workload fluctuation and other eventualities, resulting in reliability problems. But, Eastwood says, companies are using virtualization to try to push their servers to 50- or even 70-per-cent utilization.

Another big plus of virtualization is that each virtual machine and everything on it can be saved as a single file. This makes backup and disaster recovery very simple — if a virtual server fails, load a saved copy onto another machine and start it up. Quebecor has used the same trick to set up identical servers at multiple locations, Happychuk says, saving time it would otherwise take to fine-tune each machine.

Microsoft Corp. plans to integrate virtualization more closely with the next release of the server version of Windows. Six months after Longhorn Server ships (it's scheduled for late 2007), Microsoft plans a free add-on virtualization component. “We believe virtualization is very important,” Wittman says. “Many customers in the Longhorn time frame will be looking at it.”

Software that uses lots of processing power and does relatively less input and output works best on virtual machines, Eastwood says. Virtualization doesn't require more technical expertise than most companies have today, he says, and once companies try virtualization, many move ahead with it faster and farther than they first expected because they find it works well. “I would say this is the year that it actually becomes a mainstream platform,” he concludes.