Data has been stored on magnetic tape since the time of the earliest digital computers in the early 1950s. As HDDs grew in capacity and shrank in price, IT shops started using them for backup instead of tape. That trend continues.
"Tape's been under a lot of pressure in the enterprise," IDC analyst Robert Amatruda says.
Deduplication Drives Disk Sales
Disk-based backups can be accessed immediately, and the files navigated just like primary storage. Data deduplication, which allows information to be stored more efficiently, has helped popularize disk-based backup appliances, Amatruda says.
"It changes the economics of disk very favorably," he said. Sales of such appliances have been growing in double digits over the past few years, he said.
Still, tape remains part of backup in many shops. It's the primary backup medium at 25 percent of enterprises surveyed by ESG, and it's used for backup at 56 percent of the surveyed sites, Buffington said. By comparison, only 2 percent of enterprises said they back up directly to cloud storage.
Tape survives partly due to inertia, says Pund-IT analyst Charles King.
"A lot of it has to do with prior use and existing infrastructure investments," King says. "You've put millions of dollars into it, and it's cheaper to keep the old stuff rolling than it is to migrate to a new system."
However, tape retains the edge over HDDs and flash in many cases. Tape cartridges cost well under $100 and hold terabytes of data. They also consume less power than HDDs because they don't have to be kept spinning. When it comes to transporting very large amounts of data, shipping tapes overnight can be faster and cheaper than using a fat wide-area network pipe.
The classic use case for tape now is long-term data retention, such as holding on to tax returns or medical records. Once they go onto a tape cartridge, those files can sit for years without needing any electricity or drive maintenance.
"If you're going to do that with any kind of scale and any kind of economics, you're going to use tape," ESG's Buffington said.
That type of storage often takes the form of archiving, where it's not an extra copy of the data being stored for recovery but the primary copy of old data that may be rarely used.
"We're seeing tape really change the use case from more of a backup and recovery medium to more of an archive medium," IDC's Amatruda said.
Meanwhile, tape's speed and ease of use are improving. One key advance is Linear Tape File System (LTFS), a standard way of indexing the contents of a tape cartridge within the tape itself. The robotic systems that retrieve tapes used to rely solely on the date when the tape was made. LTFS collects all the information about what's on the tape and includes it there.