Study guide
Technical reference and lesson notes
Resilience starts with business requirements. Recovery time objective (RTO) defines how quickly a service must return, while recovery point objective (RPO) defines how much data loss is acceptable.
Map objectives to architecture
A low RTO usually requires warm or active capacity that is already available. A low RPO requires frequent replication or synchronous data protection. Both goals increase cost and complexity, so the architecture should match the stated requirement rather than simply maximizing redundancy.
Common patterns
- Backup and restore favors lower cost with longer recovery.
- Pilot light keeps critical data services ready while compute is scaled during recovery.
- Warm standby maintains a reduced-capacity copy of the environment.
- Multi-site active/active targets the shortest interruption at the highest operational cost.
Decision rule
Use the business objectives to eliminate designs that cannot meet the required recovery window before comparing implementation details.