Multi-Region Failover Architecture — AWS Solutions Architect (SAA-C03)
DR tier selection is arithmetic, not architecture preference
The scenario specifies an RTO under one minute and an RPO near zero. The candidate selects pilot light — a cost-efficient pattern using AWS-native services described as fast to activate. The exam answer requires warm standby or active-active. Pilot light requires provisioning time at failover that exceeds a sub-minute RTO. Route 53 health checks route traffic correctly, but the compute tier must already be running to meet the stated target. Each DR tier maps to a quantifiable RTO/RPO range; match the tier to the number.
What This Pattern Tests
The exam describes global availability and tests active-active vs. active-passive design. Active-active (DynamoDB Global Tables, Aurora Global Database write forwarding) serves traffic from both regions simultaneously — lower latency for global users but requires conflict resolution for concurrent writes. Active-passive (Route 53 failover, Aurora Global Database with read-only secondary) serves from one region and fails over — simpler consistency but RTO depends on failover detection and promotion time. The trap is choosing active-active without addressing write conflicts or active-passive when the scenario requires zero-downtime global access.
Decision Axis
Data consistency requirements (eventual vs. strong) and latency needs (global vs. regional) determine active-active vs. active-passive.
Associated Traps
More Top Traps on This Exam
Decision Rules
Which Route 53 routing policy natively couples endpoint health-check status to automatic cross-region traffic cutover, satisfying an RTO measured in seconds rather than minutes?
Domain Coverage
Difficulty Breakdown