Two metrics define disaster recovery requirements.
RPO (Recovery Point Objective):
Maximum acceptable data loss measured in time. RPO of hour means you can lose up to hour of data.
RTO (Recovery Time Objective):
Maximum acceptable downtime. RTO of hours means service must be restored within hours.
Examples:
- E-commerce: RPO min, RTO min
- Internal tools: RPO hours, RTO hours
- Banking: RPO , RTO minutes
Lower RPO/RTO requires more investment. Define based on business impact.