Storage virtualization--essentially amalgamating different storage devices so that they appear and are managed as one device--is making strong inroads in companies that use NAS. However, organizations that use SANs have been slower to adopt storage virtualization. That's the picture that emerges from two recently issued research reports.

A study conducted by Coughlin Associates, a technology and marketing research group, and Peripheral Concepts, a storage and storage-management consulting firm, identifies a strong trend toward the adoption of NAS virtualization. In contrast, a study conducted by IDC finds that only 8 percent of all companies use any virtualization at all, although 23 percent of the 269 respondents said that they planned to implement virtualization of some sort over the next 12 months.

Virtualization at NAS Sites
According to the Coughlin Associates/Peripheral Concepts study, 20 percent of all sites that have 1TB of data or more use some type of virtualization, and an additional 24 percent plan to implement virtualization technologies over the next year. And although the Coughlin study, which surveyed more than 2000 IT sites totaling 679 petabytes of disk storage and 4690 NAS systems, was targeted to enterprises with large NAS environments, it reveals that virtualization technology is in use at every economic tier in storage and in enterprises ranging from small-to-midsized businesses (SMBs) to huge organizations. In fact, Coughlin Associates' president Tom Coughlin told me, for him the biggest surprise in the study was that the general growth of virtualization was stronger and more widespread than he'd anticipated.

The reason for the growth is fairly straightforward, Coughlin says. Virtualization lets companies address the scaling, performance, and management issues that confront storage administrators as their NAS installations grow. More than 30 percent of the sites surveyed had more than five NAS implementations.

Coughlin points out that NAS is generally implemented as an appliance on an existing network. As more storage appliances are added, managing many discrete file systems and dealing with additions, changes, and migrations becomes very challenging. Virtualization has emerged as an attractive solution because it makes dealing with those challenges easier.

In fact, although performance is the most important criterion in selecting a NAS device, scalability is the top consideration for NAS virtualization technology. Ease of deployment is also key. Overall, 79 percent of respondents view ease of deployment as important, and 46 percent describe it as very important. The goal is to implement virtualization without disrupting the existing infrastructure. Sixty-nine percent of respondents say they want to deploy a NAS virtualization solution that doesn't require the remounting of any clients.

Companies deploy NAS virtualization primarily because they want to improve their data-migration and data-mobility functionality and leverage their existing backup and recovery procedures. "NAS is cost-effective, but as they add extra file systems it becomes a problem," Coughlin says. "Centralized NAS management addresses that."

Virtualization and SANs
The picture is very different for infrastructures that use SANs. According to the IDC study, whereas 19 percent of companies with 10,000 employees or more use some virtualization technology, few companies with 1000 to 9999 employees use virtualization at all. Interestingly, in both sectors, around one-third of the respondents indicate that they plan to explore virtualization solutions in 2006.

Several factors have curbed the growth of virtualization of SANs. First, major storage vendors have introduced three distinct approaches to implementing virtualization: through the use of an appliance, in a switch, or through an array. Over the past year, the boundaries between different approaches have begun to blur, making it harder for administrators to select a specific approach to virtualization.

In addition, since it introduced Windows Storage Server, Microsoft has been quietly establishing itself as a formidable force in storage. Some industry observers believe that Microsoft will make virtualization part of the next release of the Windows Server OS. They argue that over time, just as the boundaries between different approaches to storage virtualization have blurred, the boundary between server virtualization and storage virtualization will also become obscured. In the long run, they contend, storage virtualization will be one element of a distributed OS for servers, networks, and storage.

Although the two surveys show different results, taken together they tell the same story. Administrators are interested and aware of the potential benefits of storage virtualization. But they'll adopt the technology only when it's been proven to resolve real, pressing problems and becomes easy and cost-effective to deploy.