The number of IT shops putting server virtualization technology to use in production and pilots surpassed 50 percent in 2006, according to a survey by Forrester Research.

The research firm surveyed about 1,770 enterprise and smaller companies and found that use of server virtualization grew from 29 percent in 2005 to 40 percent in 2006, and the number of firms piloting remained flat at 11 percent.

Forrester also found that "interest and awareness" in the technology also increased in 2006. The survey shows the number of those aware but uninterested dropped from 23 percent to 17 percent in the same time period, and firms unaware of server virtualization decreased from 19 percent to 8 percent. About 92 percent of those responding said they were at least aware of the technology.

Adoption and awareness could have increased due to more commercial and open source technologies available -- and bigger marketing efforts on the part of vendors, Forrester says.

"Server virtualization moved from a niche Unix technology to mainstream use in x86 servers in many firms in 2005," reads the report released this month. "As a result server virtualization market leader VMware has to compete with Microsoft's Virtual Server product and the Xen open source virtualization technology."

Despite more vendor choices, VMware still came out on top as the virtualization vendor of choice among North American survey respondents.

More than half (53 percent) of those polled named VMware as the single vendor they would consider most for virtualization on Intel-based servers. Some 11 percent wrote in HP as their top vendor, and 9 percent chose Microsoft. IBM and Dell were also write-in choices for 9 percent and 8 percent of respondents, respectively.

Forrester also discovered that technology use isn't as varied among different-sized companies as it had been in the past. The three categories of enterprise companies -- Global 2000 (more than 20,000 employees), very large (5,000 to 19,999 employees) and large enterprise (1,000 to 4,999 employees) -- have similar adoption and awareness profiles, with 43 percent of both Global 2000 and large enterprises, and 37 percent of large enterprises already using server virtualization technology.

Small-to-midsize companies are lagging a bit behind the bigger companies. Twenty percent of those with between 500 to 999 employees and 13 percent with 100 to 499 employees have the technology in use. Another 3 percent and 4 percent, respectively, are piloting server virtualization products.

"SMBs trail by half in deployment, even though larger SMBs usually have enough x86 servers to merit server virtualization," the report states.