Multi-region systems
On this page 9 topics
Overview
Topics
- Active-active vs active-passive
- routing
- data residency
Learn first
4 h of practice (estimate)
Learning outcomes
- Compare active-passive and active-active designs by cost, complexity, RPO/RTO, and consistency.
- Design traffic routing and failover (DNS, global load balancers, health-based routing).
- Handle data residency requirements per region.
- Decide which parts of a system need to be multi-region and which do not.
Lessons
Lab and exercises
Lab
SRB-004-LAB1 · EU expansion
Outcomes: 1, 2, 3, 4 · Time: ~4 h
- Collect requirements: EU warehouses, EU data residency, RPO/RTO, latency.
- Tier components and pick active-passive or active-active per tier.
- Design the regional topology, routing, and data flows for Shop and FulfillCo.
- Estimate cost delta and write the topology review notes.
Acceptance: residency enforced by design (no restricted data flows out); cost delta estimated.
Exercises
| ID | Outcome | Task |
|---|---|---|
| SRB-004-EX01 | 1 | A product owner wants multi-region for prestige. Write the questions you ask. |
| SRB-004-EX02 | 1 | Compare active-passive and active-active for checkout by cost, RPO, RTO, consistency. |
| SRB-004-EX03 | 2 | Design routing and health checks for the order API across two regions. |
| SRB-004-EX04 | 3 | List data flows that could violate EU residency in the FulfillCo design. |
| SRB-004-EX05 | 4 | Tier ten components into must/should/need not be multi-region. |
| SRB-004-EX06 | 4 | Find hidden single-region dependencies in a topology diagram and fix them. |
Show solutions
- EX01 Which failure or law or latency problem? What RPO/RTO? Budget? Which components?
- EX02 Active-passive: cheaper, RPO > 0, RTO minutes; active-active: costlier, near-zero RTO, conflict handling needed.
- EX03 Global load balancer with health checks hitting a deep health endpoint (database and broker reachable), thresholds to avoid flapping, manual override.
- EX04 Logs, backups, analytics, support tooling, cross-region replication, CI test data.
- EX05 Checkout and stock reservation tier 1; tracking page tier 2; internal reports tier 3; justify each.
- EX06 Identity, secrets, CI/CD, DNS, container registry; replicate or provide a degraded path.
Workplace evidence: a multi-region or residency design you contributed to.
Quiz
Outcomes: O1 comparison · O2 routing and failover · O3 residency · O4 selective multi-region.
A self-check for you: nothing is graded, saved or sent anywhere. Choose an answer, then check it. You can try again as often as you like.
Practical part
Topology review: defend your EU design to reviewers. Pass: 70% on the quiz and a topology with enforced residency, tiering, and a cost estimate.
Common mistakes
Active-active by default; forgetting regional dependencies (identity, secrets, CI).
Assessment
Topology review.
Workplace evidence
A multi-region or residency design you contributed to.
Career relevance
HA and DR architecture (ARC-019) and compliance (ARC-029).