VMware is readying software to enable users to move virtual machines among physical servers in response to resource demands.

VMware Control Center, which is in beta testing now and is scheduled to be available later this year, provides a centralized point for managing multiple virtual servers on heterogeneous systems. It includes technology called VMotion that the company says moves live, operating applications from one physical machine to another without disruption.

In the past, VMware customers had to turn off servers to move the virtual machines, which are basically software files that contain operating systems and applications. Using VMware's software, corporations can carve multiple virtual servers out of single physical boxes.

"The VMotion technology allows you to seamlessly move live applications from one physical server to another physical server with essentially minimal network latency," says Michael Mullany, senior director of product management at VMware. "And it's transparent to the end user."

To address network latency, VMware recommends that customers use dedicated Gigabit Ethernet links to interconnect servers and blades that will be sharing virtual machines. VMotion runs with VMware's ESX Server virtual machine product.

VMotion, along with the Control Center product that runs with both ESX Server and GSX Server, will enable users to get more efficient use of their servers by matching software needs with hardware resources, Mullany says.

"This is an absolutely crucial milestone on the way to utility computing because without this, your operating system and your application are essentially stuck on the server that you installed them on," he says.

Control Center also enables users to monitor virtual machine performance and availability and move virtual machines across servers to ensure they're being used as efficiently as possible. In addition, it uses a delegated administrator model so that management rights can be restricted based on a user's position within an organization.

Analysts say VMware is taking the next logical step with its technology that is designed to help companies consolidate their server infrastructures.

"Virtual machines are nice, but now I've got them all over the place and it's a manageability headache. Control Center makes it much more realistic to run a bunch of virtual servers," says Frank Gillett, an analyst with Forrester Research.