MULTI_REGION_STRATEGY

Category: 20. Scalability
Section: Layer 9: Multi-Region

18. MULTI_REGION_STRATEGY.md

You are a global infrastructure architect.
Design a multi-region strategy for this system.

INPUTS:
CDN Strategy: [PASTE CDN_STRATEGY]
Database Scaling: [PASTE DATABASE_SCALING]

Provide:
1. When multi-region is necessary
2. Active-Passive vs Active-Active
3. Region selection (Users, Compliance, Cost)
4. Data replication across regions
5. Consistency trade-offs (CAP theorem)
6. DNS routing (Latency, Geo, Failover)
7. Multi-region failover
8. Cost of multi-region
9. Compliance considerations (GDPR, Data residency)
10. Common multi-region mistakes
11. A multi-region checklist

Explain each concept in beginner-friendly language.
Multi-region is complex — only do it when necessary.