Storage virtualization: It?s promising but users are holding back

Computerworld - Storage virtualization is a technology that holds much promise for IT managers, who see it as a way to give users a pool of virtual storage that would ease some of the headaches associated with managing a large, multivendor storage infrastructure.
Yet while some companies are using virtual storage products for certain applications, many are still holding back. Several factors, including ongoing marketplace confusion, interoperability problems and a lack of standards, are hindering the widespread adoption of the technology.
Storage virtualization was designed to let managers easily add and manage storage from multiple vendors and to allow any application or system to immediately access a pool of storage. Because virtualization software was designed to deliver storage on different devices as one central pool, management of storage should be easier.
But experts say that the technology is immature and that there's confusion about which vendors are offering true virtualization and to what extent. Part of the confusion comes from the term storage virtualization itself, which means different things to different vendors. Vendors apply different degrees of virtualization to their products, and they can deploy it in different places such as the host or in storage-area network (SAN) components.
The Storage Networking Industry Association (SNIA) has drafted a broad definition of storage virtualization, but there remains a lack of clarity in the marketplace.
"There's a lot of confusion and a lack of good data identifying the optimal place to layer in [virtualization] technology," says Steve Pomposi, head of storage management at insurance company Aetna Inc. in Hartford, Conn.
What can be done to help clarify things? "First, vendors should clearly articulate what they specifically mean by virtualization; for example, what functions are they providing, and what problems are they solving," says Steve Duplessie, an analyst at Enterprise Storage Group Inc. in Milford, Mass.
An even bigger problem is a lack of interoperability among storage virtualization products designed for different computing environments.
"There's a lack of heterogeneous support across not just storage platforms, but servers and server software that assists in the management of storage," says Pomposi. "There are [virtualization] solutions out there that are starting to make sense for homogeneous Windows environments where you're running similar software across a variety of servers. But when you include a Unix environment, it becomes very problematic."
There's also an issue of melding virtualization with existing storage management applications. "A lot of the functionality in virtualization products could become substitutes for products companies are already using and are happy with," says Anders Lofgren, an analyst at Giga Information Group Inc. in Cambridge, Mass. "They have to consider integrating with other storage platforms."
Many believe that industry standards will help vendors achieve greater interoperability, and there are some positive signs. The SNIA has been pushing a standard based on the Common Information Model (CIM), and that effort is gaining momentum .
But for the most part, IT departments are taking a wait-and-see approach to virtualization.
"To date, we have not seen huge demand for storage virtualization," says Lofgren. "The technology looks great, and if you're using it on a tactical basis to solve a specific problem, that's fine. But I think [broader] implementation is still in the future. We're recommending that companies hold off making evaluations of the technology as a strategic storage platform for at least another 12 months."
Aetna's Pomposi agrees. "It would be extremely risky at this point for a large corporation to jump into this in a big way," he says.
Still, virtualization is attracting established storage vendors and start-ups, as well as actual users.
Community Health Network in Indianapolis is using a networked storage virtualization product from DataCore Software Corp. in Fort Lauderdale, Fla., to store information such as patient records. Community Health Network, which comprises four hospitals and more than 60 other health care facilities in central Indiana, installed a primary SAN and a second SAN for disaster recovery.
DataCore's storage networking and virtualization software manages 6TB of capacity. Chris Stewart, team leader for enterprise storage, says the software consolidates heterogeneous storage resources into a virtual pool, allowing Community Health Network to access needed storage over an Ethernet link.
"With virtualization, we can present one or two terabytes of storage for any kind of hardware and only use that storage space that a particular application needs," Stewart says. "Before, we were burning a lot of storage disks. This gives us more flexibility." Community Health Network plans to move other applications to the SAN during the next month or so.

Violino is a freelance writer in Massapequa Park, N.Y.

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