Backup

This article is about duplicate data in computer systems for data recovery. For other uses, see Backup (disambiguation).
"Restore" redirects here. For other uses, see Restore (disambiguation).

In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "back up", whereas the noun and adjective form is "backup".[1] Backups can be used to recover data after its loss from data deletion or corruption, or to recover data from an earlier time. [2] Backups provide a simple form of IT disaster recovery; however not all backup systems are able to reconstitute a computer system or other complex configuration such as a computer cluster, active directory server, or database server.[3]

A backup system contains at least one copy of all data considered worth saving. The data storage requirements can be large. An information repository model may be used to provide structure to this storage. There are different types of data storage devices used for copying backups of data that is already in secondary storage onto archive files.[note 1][4] There are also different ways these devices can be arranged to provide geographic dispersion,[5] data security, and portability.

Data is selected, extracted, and manipulated for storage. The process can include methods for dealing with live data, including open files, as well as compression, encryption, and de-duplication. Additional techniques apply to enterprise client-server backup. Backup schemes may include dry runs that validate the reliability of the data being backed up. There are limitations[6] and human factors involved in any backup scheme.

  1. ^ "back•up". The American Heritage Dictionary of the English Language. Houghton Mifflin Harcourt. 2018. Retrieved 9 May 2018.
  2. ^ S. Nelson (2011). "Chapter 1: Introduction to Backup and Recovery". Pro Data Backup and Recovery. Apress. pp. 1–16. ISBN 978-1-4302-2663-5. Retrieved 8 May 2018.
  3. ^ Cougias, D.J.; Heiberger, E.L.; Koop, K. (2003). "Chapter 1: What's a Disaster Without a Recovery?". The Backup Book: Disaster Recovery from Desktop to Data Center. Network Frontiers. pp. 1–14. ISBN 0-9729039-0-9.
  4. ^ Joe Kissell (2007). Take Control of Mac OS X Backups (PDF) (Version 2.0 ed.). Ithaca, NY: TidBITS Electronic Publishing. pp. 18–20 ("The Archive", meaning information repository, including versioning), 24 (client-server), 82–83 (archive file), 112–114 (Off-site storage backup rotation scheme), 126–141 (old Retrospect terminology and GUI—still used in Windows variant), 165 (client-server), 128 (subvolume—later renamed Favorite Folder in Macintosh variant). ISBN 978-0-9759503-0-2. Archived from the original (PDF) on 1 December 2020. Retrieved 17 May 2019.
  5. ^ Ensuring the complete destruction of the primary site will not result in the loss of the recovery site by locating them physically far away.
    ".ORG Sponsorship Proposal - Technical Plan - Physical Security". ICANN.
  6. ^ Terry Sullivan (11 January 2018). "A Beginner's Guide to Backing Up Photos". The New York Times. a hard drive ... an established company ... declared bankruptcy ... where many ... had ...


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