Storage virtualization helps support the 5 million changes his global network of 100,000 vendors makes to his inventory database daily. The database's size and churn rate create a huge and dynamic demand for high-performance storage. "Our inventory database is the heart and soul of our business - the source of a competitive advantage as well as technical challenges," Schaffer says.

Today, Schaffer easily can allocate 100GB to one host or 1TB to another without worrying about the device-level details. "I do not know nor particularly care which drives are involved," he says.

The 3Par system, which includes a mix of Advanced Technology Attachment and fast Fibre Channel drives, moves data automatically among storage tiers, Schaffer says. "Without downtime, I can move data from Fibre Channel to near-line storage or from a RAID 5 to a RAID 10 set" - and this happens without detailed planning and LUN carving, he adds.

Data deduplication, another popular storage-virtualization offshoot, is on Schaffer's wish list for its space-saving capabilities. Deduplication removes similar blocks of data and replaces them with hash marks, a process that offers such benefits as an increase in the time archives can be on disk, and better backup performance. The technology, however, requires a fundamental change in the way enterprise IT managers think about storage, Forrester's Reichman says. "For years, they have used multiple copies of data to ensure protection and availability. This is a case of the pendulum swinging the other way and reducing the physical copies to create a smaller footprint overall," he says.

Experts say enterprise IT managers could ease virtualization with a popular technology used with physical storage: snapshots. "Often overlooked, this is a good feature for making virtual backup easy, enabling migration, and for development teams, which can have an endless number of identical copies of production to data test new revisions against," says Mark Peters, analyst at Enterprise Strategies Group (ESG).

Now, the bad news

IT executives are finding success with single-vendor approaches to storage virtualization, but they admit that lack of vendor interoperability and other issues continue to stymie their attempts at utility storage.

Interoperability - or lack thereof - recently factored into Mercury's latest storage virtualization plans. The company plans on deploying file-system virtualization to reduce the number of storage entry points via servers it has around its network. Again, to avoid possible support issues, Mercury is leaning toward IBM's implementation of file virtualization technology from Network Appliance.

"Even if another product's features are similar, we have to consider our decision from an interoperability standpoint," Kreisa says.

This fait accompli surrounding interoperability has Ted Ritter, research analyst at Nemertes Research Group, pessimistic about the chances of storage becoming a utility soon. "If virtualization is limited because you're so closely tied to a single vendor, then you can't get to a utility utopia," he says.

Support for the basic Fibre Channel protocol doesn't mean much here. Managing storage devices and doing things like mirroring and moving copy aren't always compatible across different vendors, he adds.

Forrester's Reichman concurs. "Today, if you have one vendor's storage behind another vendor's virtualization console, it's very difficult to troubleshoot problems. A lot of finger-pointing ensues. This problem could be solved by making the virtualization and physical storage infrastructure more standardized," he says.