Disaster Recovery
The plans and processes for restoring systems and data from backups after a major outage.
Disaster recovery↗ (DR) is the set of plans and processes prepared to restore systems and data from backups and return to normal operation after a major disruption, a cyberattack↗, hardware failure, natural disaster, or human error. Its focus is the question: "how do we recover once something bad has happened?"
A good disaster recovery plan answers concrete questions in advance: where backups are kept and how often they're taken, how quickly systems must be brought back online after an outage (recovery time objective, RTO), and how much data loss is acceptable at most (recovery point objective, RPO). It also defines which systems get restored in what order, and who is responsible for what during the process.
The most commonly overlooked but most critical aspect of a disaster recovery plan is that it must be tested regularly. A plan that looks perfect on paper but has never been rehearsed can fail exactly when it's needed, due to missing backups, steps that don't work, or a recovery that takes far longer than expected. That is why DR is an inseparable part of broader business continuity↗ planning and cyber resilience↗.