LPI Linux Certification in a Nutshell, 2nd Edition

Objective 5: Maintain an Effective Data Backup Strategy

Regardless of how careful we are or how robust our hardware might be, it is highly likely that sometimes data will be lost. Though fatal system problems are rare, accidentally deleted files or mistakes using mv or cp are common. Routine system backup is essential to avoid losing precious data.

There are many reasons to routinely back up your systems:

• Protection against disk failures

• Protection against accidental file deletion and corruption

• Protection against disasters, such as fire, water, or vandalism

• Retention of historical data

• Creation of multiple copies of data, with one or more copies stored at off-site locations for redundancy

All of these reasons for creating a backup strategy could be summarized as insurance. Far too much time and effort goes into a computer system to allow random incidents to force repeated work.

Backup Concepts and Strategies

Most backup strategies involve copying data between at least two locations. At a prescribed time, data is transferred from a source medium (such as a hard disk) to some form of backup medium. Backup media are usually removable and include tapes, floppy disks, Zip disks, and so on. These media are relatively inexpensive, compact, and easy to store off-site. On the other hand, they are slow relative to hard disk drives.

Backup types

Backups are usually run in one of three general forms:

Full backup

A full, or complete, backup saves all of the files on your system. Depending on circumstances, ...