Midrange tape keeps on rolling

Just as the servers running Microsoft Corp. Windows 2000 and Unix software have proliferated among federal agencies during the past few years, so too have the tape drives and libraries that store backup and archival copies of data created on those computers.

The extremely competitive market for midrange tape systems — called that because they typically work with computers larger than a stand-alone PC but smaller than a mainframe — is a real bonus for buyers, who benefit from swift product enhancements and favorable prices.

The latest lead change in this ongoing pony race, at least in terms of performance, occurred last week when midrange tape titan Quantum Corp. started shipping its new SDLT 320 tape drives. SDLT, or Super DLT, is jockeying for position with several other tape formats being used, including Linear Tape-Open (LTO) and Advanced Intelligent Tape (AIT).

The SDLT 320 drive can store 160G of uncompressed data on a single tape cartridge, or 60 percent more than the nearest competing formats, LTO Ultrium 1 and AIT-3. The SDLT 320 can read or write uncompressed data at a speed of 16 megabytes per second, also much faster than the competitors.

Those capacity and performance figures are doubled when the SDLT 320's built-in 2-to-1 compression is turned on, a feature available in all the midrange tape drives.

Quantum was able to squeeze more performance out of the new drives while using the same tape cartridges as the previous generation platform, the SDLT 220, by increasing the number of bits recorded per each inch of tape from 130,000 to 190,000, said Jim Jonez, Quantum's director of drive product marketing.

With prices for midrange tape products all in the same neighborhood, capacity and performance often play a big role in buying decisions.

For example, the Naval Undersea Warfare Center in Newport, R.I., was in the market about six months ago for a tape system that could store archive copies of sonar data accessed by various Unix servers and Windows 2000 workstations.

The center was already using some older tape systems, but they were not well suited to the roughly one terabyte of data created during each sonar test. The center picked Quantum's SDLT 220, which at 110G of storage capacity per tape cartridge narrowly edged out the competition.

"We took a look at the [application] specs we had and the data throughput and capacity we needed, and SDLT met that," said Mike Medeiros, head of the center's signal processing branch.

Although Quantum has the largest installed base of midrange tape, it has not always been at the top of the performance pile. For several months starting in the fall of 2000, before Quantum's SDLT 220 began shipping, numerous LTO vendors gained a foothold in the market.

"A lot of LTO customers are takeaways from [SDLT] because SDLT wasn't ready yet," said Bob Abraham, president of the storage market research firm Freeman Reports. "Those customers will likely use both SDLT and LTO platforms into the future because it's costly to convert older tapes to a new format."

Indeed, future intentions are a big deal when it comes to tape for buyers and sellers. A longtime fixture in the tape market is the "road map," a diagram that vendors trot out to illustrate their platform's future upgrade plans — typically a doubling of storage capacity every two years. The idea is to reassure customers that the platform offers plenty of growing room to keep up with expanding storage needs.

However, one speed bump for the tape vendors' business plans might be the emergence of a new breed of inexpensive disk-based backup solutions, which some disk vendors are positioning as less expensive replacements for tape backup.

Abraham expects some organizations might use disks as an interim step in the backup process, with data moving first to disk and then to tape. Writing data to tapes from secondary backup disks avoids tying up a system's primary disks, he said. "Therefore, tape backups will be easier to do, which means they'll be done more often, increasing the use of tape."

Abraham also said that for archiving applications, which is quite common in government, the portability of removable tape cartridges gives tape a clear advantage over disks, which are not removable and thus cannot be easily stored off-site.