Furthermore, industry observers see NAS consuming an ever-greater share of the networked storage pie. "If NAS is between one-fifth and one-fourth of the total market, I see it going to about one-third in the next couple of years," says Arun Taneja, president and founder at Taneja Group, Hopkinton, MA.

But while one of NAS' strongest selling points is its ease of manageability, swelling NAS environments can spell trouble for users. "The big problem with NAS is that [the devices] are islands unto themselves," says Taneja. For example, "What happens if I want to move info from NAS box 1 to NAS box 52?"

That's exactly the problem at Rosetta Inpharmatics, a Seattle biotech firm with 137TB of raw capacity across a Network Appliance (NetApp) 960c and 960, and three NearStores. For Linda Loux, manager of Windows operations, it's difficult to predict how much capacity a given project will need, and volumes fill up while others remain empty. She's dealt with that by scheduling data migrations four times per year. But even though she performs them in the middle of the night, there are enough Rosetta researchers who are night owls that it's "always inconvenient for someone."

Through NetApp, Loux learned about Rainfinity, whose RainStorage appliance enables data migration on NAS, NFS and CIFS environments transparently to the user. That led her to migrate data more frequently during the day, but in smaller increments, Loux reports. The users "don't notice that data is being moved at all," she says.

Rainfinity has garnered the approval of another up-and-coming NAS player--EMC, which played a close second to NetApp's No. 1 spot last year. Last month, EMC added Rainfinity to its list of Select Partners, bringing the total up to nine vendors. Rainfinity's Network File Virtualization platform version 4.5 has also been updated to support EMC NAS environments.

RainStorage hasn't solved all of Rosetta's problems. Even though researchers don't notice when data is in motion, Loux is limited to moving data around on the same filer. "You can't change the NFS mount on the users," she says. Then again, you can't trust users to make good use of their space.

Loux recently ran an analysis of her filers and found that 50% of allocated space hadn't been accessed in more than a year. This year, she plans on exploring a global namespace product--NetApp resells NuView's StorageX--which should free her up to move data to the appropriate class of storage.