Essential System Administration, 3rd Edition

Backup Media

When I first started working as a system administrator, 9-track tape was the only medium you’d consider using for a backup.^[6] That’s certainly no longer true. Today, there are many different media suitable for storing backed-up data. This section provides a quick summary of the available choices. This list includes most of the drives and media types which are in common use. The backup strategy for any particular system will often involve more than one media type.

Up-to-the-minute information about available backup devices and media may be obtained from http://www.storagemountain.com. There is also an excellent discussion in Unix Backup and Recovery.

Magnetic tape

Magnetic tape of one sort or another has been the traditional backup medium for decades. Over the years, it has taken on a variety of sizes and forms, beginning with 7-track and then 9-track tape: 1/2-inch wide tape wound around a circular reel. The introduction of plastic cartridges containing the tape and both reels was a major step forward in terms of reducing the space requirements of backup media. The first tape of this type was 1/4-inch cartridge tape (also known as QIC tape), which for a while was the medium of choice for most workstations; these tapes are still occasionally used.

Around 20 years ago, higher-capacity tapes in formats originally developed for other markets became available. 8 mm tape drives became popular in the late 1980s and are still in wide use. Originally designed for video uses, the ...