Going Tapeless

Disk-to-Disk Protection is Now a Mainstream Technology

It's been a long ride for tape storage. Magnetic tape made its debut as a data storage medium in 1952, when IBM introduced the first production computer, the IBM 701 Defense Calculator. A half century later-as some experts predict the demise of tape in the data center-at least one industry executive is in no mood for a nostalgic eulogy.

"Tape is an obsolete technology," asserts Manish Goel, senior vice president and general manager of data protection and retention solutions at Network Appliance. "It's risky, it's unreliable, and it's slow. The technology exists today-proven, stable technology-to implement cost-effective, secure data protection with no tape in the system anywhere."

Not everyone agrees. In a notable move in the opposite direction just two years ago, Sun Microsystems paid over $4 billion to acquire StorageTek, a leader in tape storage. Horizon Information Strategies estimates that more than 60 percent of the world's total data is stored on tape. And development continues on higher-capacity tape drives, with Sun setting the bar most recently with the introduction of the StorageTek T10000 drive, which can store up to 500 gigabytes uncompressed on a single cartridge.

Tape is cost-effective but slow

As with all things IT, cost is still the biggest factor. On that basis, tape is the clear winner over disk: a dollar will buy you 500 megabytes worth of tape storage, but only about 100 megabytes of low-end disk storage and less than 25 megabytes on a high-end box such as an EMC Symmetrix DMX or Hitachi Data Systems Lightning 9900 series. Add in the ubiquity of tape and the large investments companies have made in training and process development, and it's not surprising that rumors of tape's imminent death are greatly exaggerated.

Nevertheless, Goel can cite reasons why more IT managers are-or should be-moving to disk-to-disk data protection. Long backup windows are a key driver, fueled by the exponential growth in enterprise data and the need to safeguard it all for compliance and other reasons.

"We have customers who are taking two and three days-that's right, days-to run their backup jobs," Goel says. "At the same time, globalization means that there are no off-hours anymore, times when servers can be taken offline for backup operations. Tape backups are just too slow to support the modern global enterprise."

Your data's not protected if you can't restore it

The reliability-or more precisely, the unreliability-of tape is another factor. Every IT administrator has horror stories about information that was backed up, but can't be restored when it's needed. The reasons vary-media failure, software glitch, human error, long restore times-but the result is the same: Important data is gone forever. "Customers tell us that up to 40 percent of restore jobs either fail or take so long that they're not practical," Goel relates.

A particularly troublesome situation is the remote office, which affects more and more enterprises. Many distributed companies install local tape drives and try to manage them from a central location, with varying degrees of success. For IT Manager Steve Wilson of Cincinnati Thermal Spray (CTS), eliminating tape drives at the company's remote locations in favor of centralized disk-to-disk backups made his life easier-and greatly improved data protection.

"Managing tape drives in our remote locations was an absolute nightmare. Without dedicated IT staff on site, we had to rely on someone who had no IT training and little motivation to learn. If that person got sick or didn't come in, the tape rotation cycle could get out of sync, and today's backup might overwrite yesterday's.

"Tape movement was also problematical. You never knew if the backup tape had made it to the fireproof safe, or was sitting around somewhere-maybe on a magnet! I just didn't have the confidence that important information would be there when we needed it."

Changing backup software spurs move to disk-to-disk

CTS had other problems, including an aging, highly unreliable backup software product. Frustrated by that product's inability to complete a successful backup, Wilson went shopping. "We decided on Symantec Backup Exec as the best replacement product available. Then, I looked at Backup Exec's continuous protection features and a light bulb went off. I realized this could be the solution to the remote backup problem as well."

Wilson and his staff mocked up the replication architecture in his lab using a beta version of Backup Exec 10d and convinced themselves that it would work in the real world. As soon as the product was released, they implemented it throughout the company, and then later upgraded to 11d. Originally, CTS used an AMS Dakota-RAID system for backups. The company has recently augmented its primary storage with a Cybernetics 2TB SAN storage system.

Restores while you wait

It's delivered on the promise. "I don't worry about backups any more," says Wilson. "I never have to get on a plane with a replacement disk drive, or convince some accounting clerk to change tapes for me. Our information is safer, and I spend time now on projects that can generate revenue, make us more productive."

But it's on the restore side that the tape-less approach really shines for CTS. "The benefits of disk-to-disk backups are just out of this world. A user calls me in a panic because he's deleted some important file. Now, I can get it back while he's on the phone. In the past, it would take two or three hours best case-and it could take two or three days if the tape were sitting in someone's basement. Many users restore their own files using the Web browser interface."

Look for the opportunity to change

Wilson's story is not unusual. Customers who have switched to disk-to-disk data protection invariably point out that timing is key. Goel concurs: "We don't advocate throwing away a perfectly good tape library. But sooner or later, some disruptive event-the tape library can't scale any larger or it's reaching end of life-forces change. Then that customer has to decide, 'Do we make another substantial investment in old technology, or reconsider our approach?'"

At Agilent, the tipping point was lost productivity of its software engineers. "We were doing daily incrementals plus a full backup every weekend-a fairly standard schedule for tape-based systems," recalls Tim Dietrich, IT manager.