SWsoft last week announced upgraded Linux-based software that it says enables customers to move a virtual server and its contents to a new physical server without service interruption.

The company takes a different approach to server virtualization than such competitors as VMware and Microsoft, whose products work at the hardware level, enabling multiple operating systems to run on a single physical machine. With the SWsoft product, called Virtuozzo for Linux 3.0, multiple virtual servers run on top of a single operating system. Its virtual servers are software files that include memory, I/O, configuration files and more.

With Virtuozzo for Linux 3.0, users can move virtual servers among physical machines without having to share storage, says CEO Serguei Beloussov.

The migration capability better positions SWsoft for enterprise data centers, analysts say. VMware, for example, has offered similar technology with VMotion for more than two years.

"What these [companies] are doing now is they're trying to go from focusing on consolidation and trying to increase the utilization of a single server to more value-added features," says Scott Donahue, a vice president at Tier 1 Research. "What VMotion does and what SWsoft is doing here is they're building in fault tolerance and high availability by being able to move virtual servers between physical machines."

While SWsoft has targeted service providers in the past, "now that they have this portability feature, they'll be able to approach the enterprise more on par with some of the more traditional players like VMware and Microsoft," he says.

Other updates in Virtuozzo for Linux 3.0 include easy-to-use templates for provisioning virtual servers, streamlined resource management to create and manage virtual servers, and support for Linux distributions based on the 2.6 kernel, including Red Hat Enterprise Server 4.0.

In addition to updating its Linux product, SWsoft rolled out Virtuozzo for Windows 3.5.1, which adds a number of enhancements, including a tool enabling physical-to-virtual migration. That tool slashes the time involved with creating virtual servers from as long as days to just minutes, Beloussov says. Updates on the Windows side include enhanced performance for memory access, and support for Microsoft Windows Server 2003 Release 2 and Microsoft Small Business Server 2003.