Everybody knows virtualization isn't just about VMware anymore. Many users are past the rush to server virtualization and now need to increase the benefits of the move. They need not only to improve efficiency, performance and management, but also to find ways to extend the technology to their desktop, storage and mobile environments. That's a heavy burden. Product choices can be overwhelming, and a starting point difficult to find. Get on your way with promising products from these 10 companies:

3Leaf Systems

Founded: June 2004

Headquarters: Santa Clara, California

What does the company offer? The V-8000 Virtual I/O Server appliance, which virtualizes I/O subsystems for large pools of servers, bringing mainframe-class availability and resiliency to x86 commodity systems.

Why is it worth watching? I/O bottlenecks are a key pain point in large, virtualized server environments. "It's definitely a problem to scale up lots of virtual machines on a cluster and not be able to scale up the I/O at the same time. 3Leaf is addressing this," says John Abbott, chief analyst at the 451 Group.

How did the company get its start? 3Leaf was founded to solve such problems as the low reliability and resiliency of I/O spawned by virtualization.

How did the company get its name? Founder Bob Quinn e-mailed company supporters for ideas. Clover Systems (playing off the idea of a shamrock and Quinn's Irish heritage) was one name suggested, and it morphed into 3Leaf Systems.

Management: Quinn, who is CEO, also founded and held executive positions with Network Virtual Systems and iMODL.

Funding: US$32.5 million (AU$40.56 million) in two rounds, from Alloy Ventures, Enterprise Partners, Intel Capital and Storm Ventures.

Who's using the product? Savvis, as well as several financial institutions and a number of Fortune 100 companies.

Attune Systems

Founded: December 2003

Headquarters: Santa Clara, California.

What does the company offer? Maestro File Manager, a file-virtualization appliance that discovers, analyzes, manages and optimizes heterogeneous file-storage resources. It handles nondisruptive data migration, server retirement, data consolidation, tiering and global namespace across Windows file servers and network-attached storage.

Why is it worth watching? "Basically, it virtualizes the file server to the user," says Zak Khalil, MIS manager at Lessard Group, an architecture firm in Vienna, Va. "It runs with any existing storage. . . . It's very easy to implement, and it works."

How did the company get its start? Attune was founded in response to the explosive growth of unstructured file data and the need to manage such data better.

How did the company get its name? The founders wanted a name that conveyed a sense of control and alignment among unstructured data and storage resources.

Management: CEO Alan Kessler held the same position at Intransa and before that was COO at Palm.

Funding: About US$40 million, from Alloy Ventures, GF Private Equity Group, Quicksilver Ventures, Rock Creek Capital, RWI Ventures, Shea Ventures and Shoreline Venture Management.

Who's using the product? Bluesocket, Central Florida YMCA, Granite Telecommunications, Interwoven, Insulet and Lessard Group.