Backup
In information technology, a backup, or the process of backing up, refers to the copying and archiving of computer data so it may be used to restore the original after a data loss event.
Contents
Purposes
Backups have two distinct purposes.
- Recovering from data loss
- Recovering earlier versions
Recovering from data loss
The primary purpose is recovering from data loss, be it by data deletion or corruption.
Data loss can be a common experience of computer users. A 2008 survey found that 66% of respondents had lost files on their home PC.
Recovering earlier versions
The secondary purpose of backups is to recover data from an earlier time, according to a user-defined data retention policy, typically configured within a backup application for how long copies of data are required.
See Revision system.
Backups alone not disaster recovery
Though backups popularly represent a simple form of disaster recovery, and should be part of a disaster recovery plan, by themselves, backups should not alone be considered disaster recovery.
One reason for this is that not all backup systems or backup applications are able to reconstitute a computer system or other complex configurations such as a computer cluster, active directory servers, or a database server, by restoring only data from a backup.
Data storage requirements
Since a backup system contains at least one copy of all data worth saving, the data storage requirements can be significant.
Organizing this storage space and managing the backup process can be a complicated undertaking.
A data repository model can be used to provide structure to the storage.
There are many different types of data storage devices that are useful for making backups.
There are also many different ways in which these devices can be arranged to provide geographic redundancy, data security, and software portability.
Preparing data for backup
Before data are sent to their storage locations, they are selected, extracted, and manipulated.
Backup techniques
Many different techniques have been developed to optimize the backup procedure.
These include optimizations for dealing with open files and live data sources as well as compression, encryption, and de-duplication, among others.
Every backup scheme should include dry runs that validate the reliability of the data being backed up.
Limitations and human factors
It is important to recognize the limitations and human factors involved in any backup scheme.
Verb versus noun
The verb form is to back up in two words, whereas the noun is backup.
See also
External links
- Backup @ Wikipedia
