How Tape Shapes Up

By Baselinemag  |  Posted 2004-01-16 Print this article Print

Tape remains the leader of the backup pack, delivering more bytes for the storage buck than even the lowest-cost disk drives.

Tape remains the leader of the backup pack, delivering more bytes for the storage buck than even the lowest-cost disk drives.

There's something about tape storage redolent of another computing era. The spinning spools of magnetic tape, the gigantic tape libraries with robotic cartridge-picking arms—it all seems more at home in a mainframe shop circa 1975 than in a sleek 21st century data center.

But tape still plays a central role in the data protection strategies of nearly every business. No other medium can store massive quantities of information more cost-effectively than tape, especially when it's placed in large automated libraries, whose "stacks" are jukebox-like devices that can hold thousands of tapes.

"We just need a ton of storage," says Corey Van Allen, director of information technology at Primary Color, a printing company in Southern California that stores large media files for its clients in the entertainment and advertising industries. "It would be prohibitively expensive to put it all on disk." The company's four Quantum libraries hold a total of 1,300 individual tape cartridges with a whopping 60 trillion pieces of data. Even premium-grade tape cartridges, at 50 to 75 cents per billion bytes, cost less than one-tenth as much as the cheapest disk available.

More broadly, tape thrives because every information technology executive worth his or her onions recognizes the absolute need to keep copies of any data that affects operations or financial results. Obviously, companies must ensure they can conduct business even if their primary databases go haywire. But also underscoring the importance of tape storage are government regulations, such as the Health Insurance Portability and Accountability Act (HIPAA) in the healthcare arena, which are forcing organizations to retain electronic records for years—or even decades.

Because backup and archiving systems are effectively insurance policies for data, reliability is everything. Seasoned backup administrators like tape storage because it's proven to be extremely dependable. "I've been working in the I.T. field for 20 years, and it's rare that I've ever seen a tape go bad," says Gabriel Calderon, a systems administrator who handles backup for the Denver International Airport.

The next generation of tape storage products promises to pack even more data into smaller spaces. Storage Technology, which pioneered the tape library category in the late 1980s, this year plans to introduce its biggest new entry in this segment in almost a decade: The StreamLine, which will be able to hold as many as 200,000 tapes at a density of 50 tapes per square foot.

In the library category, the two dominant tape formats—which define cartridges' physical characteristics—are Linear Tape Open (LTO), backed by Hewlett-Packard, IBM and Certance; and Quantum's Super Digital Linear Tape (SDLT). In 2000, the Linear Tape Open consortium delivered its first products, which were bigger and faster than Quantum's tape drives at the time, and last year doubled the format's speed (to up to 35 million bytes per second) and capacity (to 200 billion bytes per tape). Quantum hasn't yet recovered: Gartner Dataquest says Linear Tape Open drives outshipped Super Digital Linear Tape two-to-one for the first nine months of 2003. "Generally people are happy with DLT, but LTO has a lot more traction," says Mark Teter, chief technology officer for Advanced Systems Group, a storage reseller based in Denver.

Still, while tape is the standard for backup and archiving today, a shift is underway toward using low-cost disk drives as the building blocks for large data repositories to supplement tape storage systems. Advanced Technology Attachment (ATA) disk drives—the variety commonly found in desktop PCs—are about a penny per million bytes, compared with typical enterprise disk storage systems that are 10 times or more expensive. In fact, the major suppliers of tape storage, including ADIC, Quantum and StorageTek, have rolled out disk-based backup systems in anticipation of changing customer requirements.

Disk is appealing as a tape alternative because it's just plain faster, despite recent advances by tape manufacturers to speed up their gear. A disk can push out data 40% faster than a tape drive can, according to storage giant EMC—and that's not even figuring the time it takes for a tape library to locate and load a cartridge, which can take upward of several minutes.

That's the weakness of tape storage: It can be agonizingly slow. Sam Gustman, executive director of technology at The Shoah Foundation, stores a 180-terabyte video archive of Holocaust survivor testimonials on an ADIC library today. "Right now, if I put 50 gigabytes on a tape and someone's trying to access it, you can wait 15 minutes while it scrolls through to find it," he says.

At some point, Gustman envisions having an uncompressed version of the archive—amounting to 15 quadrillion bytes—accessible on much faster disk storage. For the time being, though, "that's sort of a twinkle in our eye."

Most companies are in the same boat, only in the early stages of deciding how to use disk to augment their tape systems. "There's a lot of awareness of using disk for backup, but tape reigns supreme for archiving," says IDC's Robert Amatruda.

One reason: tape is still cheaper. It's also easier to move to off-site locations for safekeeping. Plus, tape media has a lifespan of 30 years or more (at least, theoretically). "I don't know that we will ever get to a totally disk-based infrastructure, unless we figure out a way to shut down disks and make sure the data doesn't get degraded," says Carlson Companies' Gary Johnson.

Early adopters already use disk to improve their backup processes—and save money. Grant Thornton, an accounting firm based in Chicago, last fall deployed a combination of short-term disk storage and tape systems to consolidate data from its 51 U.S. offices. The servers at those local offices automatically send backup jobs to EMC disk systems at four regional hubs; Storage-Tek L80 libraries then save the data to tape. Dave Johnson, the company's director of infrastructure technology, figures the software and hardware for the project cost a total of $400,000, compared with the $1.3 million per year Grant Thornton was spending on conventional backup and off-site tape storage services for each office.

What's more, the consolidated backup architecture helps Dave Johnson know exactly what data has been protected. That's crucial in complying with regulations like the Sarbanes- Oxley Act, which requires companies to keep financial data for several years. "Now we have a single, consistent copy of our data," he says. "I don't have to worry whether somebody did a backup and put the tapes in the basement."


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