Tape storage still the best backup solution

Tape storage still plays a significant role as a backup tool in network data storage even as disk prices are falling because new tape storage products from vendors such as Advanced Digital Information Corp. (ADIC), as well as improved tape formats such as Super DLT (digital linear tape), move tape storage technology forward.

Tape storage can cost as little as several hundredths of a cent per megabyte, compared with two to three cents per megabyte for disk storage, industry experts said. Vaulting tape backups at an off-site location also guards against on-site data corruption from viruses, fire, natural disasters, accidental deletions, and other data-loss issues.

These benefits of tape storage mean that tape-storage vendors such as ADIC, Quantum Corp., and Benchmark Tape Systems Corp. are not yet concerned about the decreasing costs of disk storage or about possible competition from disk-storage vendors.

“We love inexpensive disks. One of the things that you have to remember is the more data you’ve got, the more people need to manage it in a way that keeps archive copies and gets the data off the system,” and tape does all that, explained Steve Whitner, a spokesman for ADIC, in Redmond, Wash.

ADIC introduced its new Scalar 10K tape next week, an automated platform that handles from 700 to nearly 5,000 tape cartridges, and from 36 to 162 tape drives, depending on tape format. Using a robotic arm to load and unload tape cartridges, the Scalar 10K can perform 450 tape exchanges per hour, Whitner said.

With native storage capacity ranging from 35TB to 881.5TB, the ADIC Scalar 10K supports multiple tape format standards, including LTO (linear tape open), AIT (advanced intelligent tape), DLT, and the improved Super DLT format.

Super DLT holds 220GB of data per cartridge, twice that of AIT and regular DLT tape, and 20GB higher than LTO. The Scalar 10K starts at $140,000.

Bill Augustadt, chief architect of eOnline, an ASP (application service provider) with locations in Arizona, California, and Texas, is considering the ADIC Scalar 10K as eOnline prepares to add additional capacity to its tape storage.

“If you are off-siting [storage backups], tape is probably the best solution,” Augustadt said. “For practical purposes and for traditional computing reasons, we will continue to use tape until such a time when it is not necessary. And I don’t see that in the foreseeable future.”

Augustadt said eOnline backs up over 40TB of data in daily incremental backups and weekly full backups. The company plans to be backing up twice that amount by the end of this year, he said.

“Tape is a very reliable means of backing up,” Augustadt said.

Companies using disk-based backup methods such as data mirroring run the risk of losing their backup copy even if the backup disks are located off-site, said Bob Amatruda, a storage research analyst at IDC in Framingham, Massachusetts. But tape can be stored offline in a protective vault. “Disk storage is not a substitute for disaster recovery. Only tape is a true, removable disaster-recovery method,” Amatruda said.

Because of its mechanical nature, it takes a bit more time to transfer data to tape and to move cartridges in tape libraries. Thus, prior to falling disk prices, meeting a backup deadline with tape proved difficult for many companies.

But cheap disk storage now allows companies to mirror data to a disk-based staging area, where data is then moved to tape without the stress of a looming backup window, said Tony Prigmore, a senior analyst at The Enterprise Storage Group in Milford, Mass.