Storage virtualisation adds to your costs, but if your goal is to manage your storage networks more efficiently, it pays off.

Storage virtualisation is becoming more common as companies realise the benefits of consolidating storage-area networks and streamlining their management. As with applications and servers, storage virtualisation enables IT departments to decouple data from dedicated devices.

An appliance serves as a go-between from applications and operating systems to the mass storage, enabling you to manage them all using one console. Thirty-eight percent of IT professionals surveyed recently by CIO said they are piloting or have deployed virtual storage technology, and another 31 percent are interested in it.

Why you care

Virtual storage appliances can extend the life of your legacy storage or help you migrate more easily to new devices through thin provisioning, says Gene Ruth, a senior analyst with Gartner. The virtual appliance automatically maps your data to the usable physical storage space. Though you still have to contend with the physical devices, Ruth says that for day-to-day management, there is a clear benefit to using one console.

At Sunrise Senior Living, support calls dropped 62% after VP of Technology Samir Shah deployed a NetApp storage virtualisation system that reduced performance problems caused by faulty disk arrays. The company, which operates in four countries, is saving $70,000 a month.

For Peter Haas, the director of IT at the Louisiana Supreme Court, managing redundancy and disaster recovery became a nightmare when attorneys switched to electronic document management and embraced video and audio note-taking. Virtual storage, integrated with a disaster-recovery system from CA, made it possible to manage multiple instances of data more easily.

The real deal

Andrew Reichman, a Forrester analyst, says that too often, IT leaders assume the main advantage to virtualisation is being able to source storage from multiple vendors; they want to choose the lowest-cost option whenever more capacity is needed, and use the storage appliance to manage the various devices. Vendors have promised this capability, Reichman says, but they haven't yet delivered. "There is a support challenge in having one vendor manage storage arrays from another," he says.

Virtualisation still makes it easier to refresh your storage gear, Reichman says, by making the process less disruptive than configuring each new device individually. But beware if you're layering virtual storage on top of legacy systems, notes Ruth: Storage virtualisation vendors may only support currently popular disk arrays. Otherwise, follow the same rules you would in any data migration: Wait until off-hours, and make sure you've backed up everything.

What you should do

Reichman notes that adding a virtual storage layer to your network adds to your budget. He advises modelling the costs before taking the plunge, but he says that in an environment in which vendors are compatible, single-console management can provide greater management efficiency. That made the investment worthwhile for Terry Tick, vice president of IT at CI Investments; the CommVault virtual storage platform he deployed cut back-up time by about half.