8.2.4. Backup Media

We have been very careful to use the term "backup media" throughout the previous sections. There is a reason for that. Most experienced system administrators usually think about backups in terms of reading and writing tapes, but today there are other options.
At one time, tape devices were the only removable media devices that could reasonably be used for backup purposes. However, this has changed. In the following sections we look at the most popular backup media, and review their advantages as well as their disadvantages.

8.2.4.1. Tape

Tape was the first widely-used removable data storage medium. It has the benefits of low media cost and reasonably-good storage capacity. However, tape has some disadvantages -- it is subject to wear, and data access on tape is sequential in nature.
These factors mean that it is necessary to keep track of tape usage (retiring tapes once they have reached the end of their useful life), and that searching for a specific file on tape can be a lengthy proposition.
On the other hand, tape is one of the most inexpensive mass storage media available, and it has a long history of reliability. This means that building a good-sized tape library need not consume a large part of your budget, and you can count on it being usable now and in the future.