A few days ago, the Linear Tape Open (LTO) consortium -- whose member include Hewlett-Packard, IBM, and Quantum -- officially released specifications for the next generation of the LTO Ultrium standard, LTO Generation 5. This may sound a little retrograde. With all of the incredible advances made in other storage technologies, can tape maintain its relevancy into the future? Can Virtual Tape Libraries (VTL), removable disk, or the cloud replace the need for constant management of tape-based backup and archiving systems?
To answer these and other questions, let's look at what tape does well and why it has been an indispensable part of the data center for the past 30 or 40 years. The pinnacle of existing tape backup technology currently provides three main benefits.
[ Get the big picture on backups in W. Curtis Preston's Backup Deep Dive Report. ]
First, tape is able to store a lot of data in a very small package. Second, currently available tape drives can deliver sequential transfer speeds that rival the fastest hard disks available. Finally, tape media can be removed from its drive, shipped, stored, and used years later.
As Andrew Tanenbaum, the famous computer science professor and textbook author, once said: "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."
Over the years, tape backup media has maintained parity with the disks it backs up. The current generation of the LTO standard, LTO-4, can natively store 800GB (uncompressed) on a single tape that occupies a little over 14 cubic inches. The LTO-5 standard will roughly double that native capacity to around 1,500GB per tape, yielding a total density by volume of about 107GB per cubic inch. The largest standard internal 3.5-inch SATA disk can hold about 2TB in a package occupying about 23 cubic inches, for a density of about 86GB per cubic inch. If you are planning on packing the entire Internet into the back of an Oldsmobile, tape is still your best option.
