Expert
No region depends on another
An electronics marketplace runs active-active in Paris and Frankfurt, with an order database replicated across three regions. Yet every request, in both regions, calls a pricing and VAT service that only runs in Paris. At 17:00 Paris goes down for two hours. Keep the marketplace selling.
Prices and VAT rates must be exact: a cached or default price is not acceptable, so no fallback answer may be served. The pricing service is stateless; its rates ship with each release.
What your design must achieve
- Availability ≥ 99.95 %
- Latency p99 < 300 ms