Learning series · 6 episodes · Principal / Staff
Designing Reliable Multi-Region Systems
Six connected engineering decisions: single to multi-region, three-region quorum, active-active authority, eU data residency, regional failover capacity, safe failback.
Start series →Follow the decisions in order
- Part 1 of 6
Principal
How would you migrate a stateful service from one region to multiple regions?Finding single-region assumptions, data replication and routing.
- Part 2 of 6
Staff
How would you place a three-region write quorum to balance latency and consistency?Quorum placement and leader location.
- Part 3 of 6
Staff
How would you design active-active writes across two regions without losing updates?Home regions per record and conflict handling.
- Part 4 of 6
Staff
How would you design a global service that keeps EU customer data inside the EU?Partitioning by jurisdiction and what can stay global.
- Part 5 of 6
Staff
How would you fail over regional traffic without overwhelming the healthy region?Capacity, cold caches, lag and control-plane dependencies.
- Part 6 of 6
Principal
How would you safely fail back after six hours of writes in the recovery region?Failback, stale authority and reconciliation.