Distributed Systems: Expect Failure

The fundamental challenge of distributed systems is not performance or scalability — it is failure. Networks partition. Servers crash. Clocks drift. Messages arrive out of order, or not at all. These are not edge cases; they are the normal operating conditions.

Designing for failure means embracing eventual consistency, building idempotent operations, and always asking: what happens when this call fails? The CAP theorem tells us we cannot have everything, so we must make deliberate tradeoffs between consistency and availability.

The best distributed systems are boring. They use well-understood patterns: circuit breakers, retry with exponential backoff, dead letter queues, and saga patterns. Innovation in distributed systems comes from combining these patterns wisely, not from inventing new ones.