Database Backup is the activity of copying a database to permanent storage. It will be preserved in case of equipment failure. Equipment failures include system crashes, disk damage, etc. The backup copy can then be used to restore data. The backup must be kept synchronized with the primary copy of the database. One should copy the primary database onto the backup every day, every week, or every month depending on your need. Generally, the backup copy of the database is kept separate from the primary copy.
Importance of Backups:
i. A backup increases the availability of data.
ii. Planning backup is that make sure a current copy of the database is always available even in case of a disaster such as fire, flood, earthquake, virus attack, disk crash, etc.
Types of Backups:
Backups are mainly two types:
- Immediate Backup
- Archival Backup
Immediate Backups are kept on a floppy disk, zip disk, hard disk, or magnetic tape. It comes in handy when a technical fault occurs in the primary database such as a system failure, disk crash, network failure, or accidental erasure of data. Damage due to virus attacks is also repaired by the Immediate Backup.
Archival Backups are kept in mass storage devices such as magnetic tape, CD-ROMs, Internet Servers, etc. It is very useful for recovering data after a disaster such as fire, earthquake, flood, etc. Archival Backups should be kept at a different site other than where the system is functioning. Archival Backup at a separate place remains safe from thefts and intentional destruction by user staff.