Data backup

A separate copy of data kept so the original can be restored after loss, corruption, or damage. Backups are distinguished from synchronized copies, which may reproduce unwanted changes or deletions.

Full backup: A backup containing every selected file or data item at the time it is made. It provides a complete restore point but requires the most storage and copying time.
Disaster recovery: The processes for restoring technology and operations after a disruptive event. Backups supply recoverable data, but disaster recovery also plans systems, people, and procedures.
3-2-1 backup rule: A backup guideline recommending three data copies, on two media types, with one copy off-site. It reduces the chance that one failure or location destroys every copy.
Data synchronization: The process of keeping data consistent across multiple devices or locations. Synchronization can propagate deletions and corruption instead of preserving an independent recovery copy.
Immutable backup: A backup protected from alteration or deletion for a specified period. Immutability can prevent attackers or mistakes from erasing recovery copies.
Incremental backup: A backup containing changes made since the most recent backup of any type. It saves storage and time, but restoration depends on the full backup and every later increment.
Business continuity: Planning that enables an organization to continue essential operations during and after disruption. Backup recovery supports continuity when data loss would interrupt essential services.
Recovery point objective: The maximum tolerable amount of data loss measured in time. It determines how frequently backups or other recovery points must be created.
Data replication: The copying of data between systems to keep multiple instances available or consistent. Replication improves availability but can reproduce harmful changes across copies.
Air gap (networking): A security measure that physically or logically isolates a system from other networks. Isolation can keep backup copies beyond the reach of network-borne attacks.

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