Tape backup is the practice of copying data to magnetic tape via an SCSI, IDE, USB or otherwise connected tape drive, either for copying,
backup and restore, or archival purposes. Magnetic tape backup is a mature technology that has existed in various forms since the 1950s, and offers a relatively low unit cost. Magnetic tapes come in a variety of sizes and capacities, with common formats including cassettes that are three-quarter inch, half-inch, eight millimieter and other sizes.
The primary disadvantage of tape backup is the inherent inefficiency in the administration of large amounts of data stored on tape, which often require an expense manually-administered tape library.
Another disadvantage of tape backup is that while disk-based data storage provides random data access, tape drive data can only be accessed sequentially, adding considerable time to any exploration of a data recovery point.
In addition, magnetic backup tape reports recovery failure rates as high as 20 to 50 percent, making it an unreliable form of data backup compared to disk-based backup systems.
Tape backup is increasingly for
archive data which is inactive or non-critical, with mission-critical data being stored on
hard disk and other more reliable storage media.
