backups

Backups are copies of data that are stored separately from the primary data store to enable recovery after data loss, corruption, or disaster. They are a fundamental component of data protection and business continuity. A backup differs from archival in that it is designed for rapid restoration of recent data, whereas archival emphasizes long-term preservation and compliance with less emphasis on speed.

Backups come in several types: full backups, which copy all selected data; incremental backups, which store only data changed since the last backup of any type; and differential backups, which store changes since the last full backup. Some systems use synthetic full backups or continuous data protection to optimize performance.

Storage options include local disk, network-attached storage, offsite facilities, and cloud services. A common guideline is the 3-2-1 rule: at least three copies of data, on two different media, with one copy kept offsite. Ransomware and disasters have driven practices such as air-gapped and immutable backups to reduce the risk of tampering or rapid encryption.

Operational practices include defining a backup schedule aligned with recovery objectives (RPO and RTO), automating backups, and performing regular verification and restore testing. Cataloging and metadata help identify and recover specific versions quickly.

Retention and security considerations include retention policies, data tiering, encryption at rest and in transit, strict access controls, and immutable backups to prevent tampering. Documentation of runbooks and contact plans supports reliable recovery.

Restoration presents its own challenges: ensure restorations are authorized, dependencies are restored in the correct order, and that performance impacts are managed. Regular drills, automated testing, and clear rollback procedures improve resilience.