Disk alone won't a comprehensive backup strategy make, however. Effectively making use of near-line backup requires a tool such as StorageTek's EchoView, a journaling storage monitor that provides a continuous backup allowing for restores to any point in time. Such capabilities will rapidly work their way into enterprise storage management solutions as near-line disk becomes even more pervasive among customers.
Ultimately, the performance and accessibility of disk is likely to find it a role in even the most tape-intensive environment. That's what happened to Data Base File Tech (DBFT) Group of British Columbia, Canada. The managed backup service provider recently installed a Quantum DX30 to provide better performance (compared with tape) when backing up and restoring as many as 20 customer servers at the same time.
"We wanted to run remote, but tapes require someone to be onsite all the time," says Maurice Auger, director of operations with DBFT. "Tapes do not have the throughput required to do that unless you have great libraries with caching systems on them. But disks are designed to look like tapes, and the software we're using, which runs best on tape libraries, ran almost flawlessly the first time. Overall, we're seeing in the order of a 4x speed improvement, and this gives the customer high availability of their data any time they want it. If we'd backed up to tape, we would probably have to get involved [in the restore]--but this way we don't."
Whatever the motivations for their embracing of disk, analysts are widely convinced that customers will increasingly flock to disk, while retaining tape as an offline archival method. Speaking last month at Gartner's "PlanetStorage 2003" conference in Las Vegas, Gartner vice president Bob Passmore proclaimed that increasingly efficient incremental backup techniques would combine with improved snapshots, mirroring and disaster recovery features to make disk the primary medium for data restores by 2008.
By then, however, current data growth figures will suggest that data will have grown to many times its current size. Tape will always be priced lower than disk (see "Cost comparison: 10TB of capacity"), and it can be transported to vaults.
Says Andrew Senior, president of tape solutions provider Avax International, of Erin, Ontario: "Tape is a nice, cheap way of keeping large amounts of data stored off-site. If you don't have sufficient historical copies, then you're dead. Tape is going to hang around for a long time."
