Disk Backup's a Red-Hot Idea

A whopping 84 percent of respondents to the most recent Byte and Switch poll say they're either already using disk-based backup or plan to do so in the next 12 months -- indicating that as a concept, at least, it's catching on rapidly.

According to the results of our May poll, just 19 percent of 103 respondents say they're using disk for backup purposes today. But another 65 percent say they expect to adopt it within the next year. Only 16 percent say they didn't see the need for it yet. (For more on this topic, see our report, Disk Backup 101.)

"It really suggests that people are getting this message faster than I would have guessed," says Kevin Daly, CEO of Avamar Inc., a startup that sells a disk-based backup system called Axion (see Avamar Gets More Dough).

The primary driver for disk-based backup, according to our poll, is faster recovery times, with 47 percent agreeing that shrinking the recovery window is the primary benefit of the technology. Meanwhile, 24 percent picked shorter backup windows; 18 percent said the ability to store vast amounts of data online was most attractive; and 11 percent agreed that "it's so dang cheap, why not?"

Dave Kenyon, product line manager for enhanced backup solutions at Quantum Corp. (NYSE: DSS) -- which sells both disk and tape systems for backup -- says enterprise users are increasingly interested in reducing the amount of time it takes to restore data."There's been a trend the last three to six months where end users are couching data protection more around recovery, instead of backup," he says. "What they're talking about now is, 'How fast can get I get X amount of information restored?' "

Kenyon says Quantum is seeing traction start to pick up this quarter for its DX line of disk backup systems. "We're getting more heavy-duty customers," he says. "The 'onesie-twosie' people are now turning into people who want an enterprise disk backup architecture."

As for the longevity of tape, most respondents believe it will remain a part of the overall data protection universe, with 40 percent agreeing that "there will always be a need for removable media" and 36 percent saying it will persist for long-term archiving. But another 21 percent believe tape will die out altogether and "go the way of the Pinto." [Ed. note: which is not to say it will burst into flame.]

Tape vendors, though, continue to maintain that the two approaches aren't competitive, but complementary. Saurin Shah, director of advanced technology and applications at Imation Corp.'s data storage division, says the removability of the media will continue to be an important differentiator for long-term storage.

"We look at disk-to-disk as secondary storage and not necessarily backup," he says. "What I mean by that is, it's staging data, which eventually you need to make a decision about whether you need to move it to tape."Others note that disk drives are not designed for "cold storage." Quantum's Kenyon says that, whereas Super Digital Linear Tape (SDLT) media is rated at 30 years of reliable life for archival purposes, a powered-down disk may start to lose data and start to demagnetize after a year or two. "Disk is designed for very fast I/O operations," he says. "The disks have to keep spinning for them to work."

In the future, disks may be designed with features that would make them better suited for long-term archival. The Information Storage Industry Consortium (INSIC), which establishes five- and 10-year technology roadmaps for the disk drive industry, has started to consider how to extend the shelf life of a powered-down disk.

"It's certainly something of interest, and people are certainly thinking about what would need to be different for disk drives for archival storage," says Paul Frank, director of INSIC. But today, most hard drive vendors are not doing any actual R&D in this area.

Ultimately, Daly believes, the adoption of disk-based backup systems is largely a cultural issue: Most IT managers are accustomed to backing up data to tape. "It's easy to show the economics, but I think no one's going to do it until they get some operational expertise with disk backup systems."

Be sure to vote in our new monthly poll: 4-Gig Fibre Channel.Todd Spangler, US Editor, Byte and Switch