Storing all of the information on your system to backup media
is called backing up your system. You back up your system so that
you have a copy of the information stored on it should it experience
a major failure that causes some or all of your files to be lost.
If your system experiences a failure, you can reload that information
from your backup media. Refer to subsequent chapters for complete
instructions on performing system backups and restoring files from
backup media after a system failure.
Planning, managing, and performing necessary system backups
are, perhaps, a system administrator's/operator's most important
tasks. Regularly scheduled, properly performed system backups guarantee
that, in the event of an unexpected system mishap, all information
present on the system at the time of the last backup is currently available.
If a system failure does occur, the amount of data lost depends
directly upon three factors:
How recently the last backup was performed.
The level of system activity since the last system backup.
The extent of the damage.
As a system administrator, you are responsible for establishing
a backup schedule that best meets the needs of your organization
and all system users. For example, the schedule may include saving
all files in a particular account every day, or more commonly, copying only
those files that have been added or modified since the last complete
system backup.
You or a member of your staff are probably also responsible
for actually performing the backups. In addition to user files,
you must be sure to back up all system files since you may need
to restore these files from backup media if the system experiences problems.