Disaster Recovery

The plans and technical capabilities used to restore critical systems after a major outage or site-level failure.

Motivation

Disaster Recovery prepares an organisation for failures that exceed routine service recovery, including regional outages, data loss, destructive incidents, and loss of a primary facility or provider.

Recovery objectives

RTO — Recovery Time Objective: the maximum acceptable time to restore a service or business capability.
RPO — Recovery Point Objective: the maximum acceptable amount of data loss, expressed as time.

Core capabilities

A DR strategy combines dependency mapping, backups, replication, alternate capacity, failover procedures, communication plans, access controls, and regularly exercised recovery runbooks.

Common strategies

Backup and restore.
Pilot light.
Warm standby.
Active-passive failover.
Multi-region or active-active operation.

Common mistakes

Confusing high availability with disaster recovery.
Defining objectives without testing actual recovery times and restore points.
Protecting infrastructure while ignoring identity, DNS, third-party dependencies, and operational access.
Treating an untested recovery plan as a working capability.