Take Zambeel, Fremont, CA, for example, and its recently announced Aztera, a NAS device that "provides massive scalability in both capacity and performance, while maintaining a single system management view," the company says.

Aztera derives these capabilities from its software - clustering, operating system support, policy-based management, and yes, virtualization - and not hardware, which consists of generic commercial off-the-shelf components such as Intel CPU blades, a Gigabit Ethernet switching fabric, and ATA disk drives.

There are different ways to do virtualization within a box. LeftHand Networks, with its IP-based NSM100, virtualizes data on its disk at the block rather than file level, says Bill Chambers, president and CEO. That way, "we can support both [block-oriented] Oracle and MS Exchange, as well as more static [file-based] data," Chambers says.

Broadband Storage, another start-up which recently emerged from stealth mode, is using virtualization at the core of its Scalable Unified Storage architecture, alongside a distributed SAN file system. Together, these two technologies will enable an array that provides automatic and non-disruptive RAID-level scalability, and allow users to migrate from DAS to SAN topology within the same array.

That's important because 67% of all storage dollars and 76% of capacity still go to DAS configurations, points out Mark Pollard, Broadband Storage vice president of marketing. A virtualization layer under the hood can insulate DAS users who might want to migrate to a SAN, but have been put off by that "scary, complex world."