Because storage virtualization technology used for these purposes copies just the individual parts of changed data, not entire files or even drive volumes as in traditional host-based storage architectures, these data-protection activities are faster and tax the network less. "You end up transferring 40 or 50 percent less, depending on the data you have," says Ashish Nadkarni, a principal consultant at the storage consultancy GlassHouse Technologies.

This efficiency lets a CIO contemplate continuous backup and replication, and enables quick moves to new equipment in case of hardware failure. "We can add new storage as needed and have data transferred in the background, without the users even knowing," says Ryan Engh, IT infrastructure manager at the investment firm Wasatch Advisors, which uses DataCore's virtualization software.

Another advantage: "This prevents the states of the disaster recovery site and the production site from pulling apart," he says, a common problem in a traditional environment where the two data sets are usually out of synch because of the long replication times needed.

Moreover, the distributed nature of the data storage gives IT great flexibility in how data is stored, says Chris Walls, president of IT services at the healthcare data management firm PHNS, which uses IBM's virtualization controller. "That control layer gives you the flexibility to put your data in a remote site, or even in multiple sites," he says, all invisible to users.

Understanding these capabilities, a CIO could thus introduce 24/7 availability and disaster recovery, perhaps as part of a global expansion strategy. That is precisely what Etcheverry is doing at Champion. "We now have a zero-window backup, and I can rebuild a drive image in almost real-time," he says.

Some enterprises have gained additional advantage from storage virtualization by combining it with an older technology called thin provisioning that fools a drive into thinking it has more capacity than it has; this is done typically to create one standard user volume configuration across all drives, so when you replace drives with larger ones, IT staff does not have to change the user-facing storage structure. By adding storage virtualization, these standardized, thin-provisioned volumes can exceed the physical limit of any drive; the excess is simply stored on another drive, without the user knowing. "This really eases configuration," says Wasatch's Engh. That also reduces IT's need to monitor individual drive usage; the virtualization software or appliance just gets more capacity where it can find it.

For example, Epilepsy Project, a research group at the University of California at San Francisco, uses thin provisioning, coupled with Network Appliance's storage virtualization appliance. The project's analysis applications generate hundreds of gigabytes of temporary data while crunching the numbers. Rather than give every researcher the Windows maximum of 2TB of storage capacity for this occasional use, CIO Michael Williams gives each one about a quarter of that physical space, then uses thin provisioning. The appliance allocates the extra space for the analysis applications' temporary data only when it's really needed, essentially juggling the storage space among the researchers.