The goals of computer backup are to completely preserve essential information and to minimize disruption of operations.
Requirements:
(1) assessment of backup needs
(2) impact assessment of how a backup affects operations
(3) determination of responsibilities
(4) security of backups
(5) protection of backups from damage
Backups can be performed:
(1) continuously (mirrored storage)
(2) hourly or daily backup
(3) weekly backup
(4) complete backup
Backups may be incremental (only things that have changed) or complete.
It is desirable to make at least 2 copies of a backup, with one copy stored someplace offsite.
Media should be stored where it is protected from heat, fire, water, electromagnetic radiation and other threats. It should also be protected from authorized access and theft.
The ability to restore from a backup should be tested. This is often done in conjunction with a test of disaster recovery procedures.
Performing a backup should not disrupt operations. Backups can be performed automatically at night or on the weekends by automated devices. Alternatively backups can be performed from a mirrored drive.
Media is one of the weakest links in backup. Media should:
(1) be of the highest quality
(2) be inspected for deterioration
(3) not overused (a problem for media used for frequent backups) by rotation in use and periodically replacement
(4) be readable (old backups may not be readable by current hardware)
(5) be sufficient for the amount of data being backed up
There are companies that specialize in retrieving information from damaged media and computer disk drives. This can be expensive.
