The Architecture of Resilient Systems
Val Chahul
The Operator
Why most systems fail—and how to build ones that do not. A deep dive into the five pillars of resilient system design.
Why most systems fail—and how to build ones that do not.
The Myth of Uptime
In my decade of building production systems, I have learned that uptime is a lagging indicator. The real measure of a system health is how it behaves when things go wrong—and things always go wrong.
Everything fails, all the time. — Werner Vogels, CTO of Amazon
This is not pessimism—it is engineering realism. The question is not whether your database will crash, your network will partition, or your third-party API will timeout. The question is: what happens next?
The Five Pillars of Resilience
Redundancy — No single point of failure should exist
Isolation — Failures should be contained, not cascading
Graceful Degradation — The system should work partially, not fail completely
Observability — You cannot fix what you cannot see
Recovery Speed — MTTR matters more than MTBF
A Real-World Example: The Circuit Breaker Pattern
const circuitBreaker = new CircuitBreaker(paymentService, {
timeout: 3000,
errorThresholdPercentage: 50,
resetTimeout: 30000
});
circuitBreaker.fallback(() => {
return { status: 'pending', message: 'Payment queued for retry' };
});The Bottom Line
Resilience is not a feature you add at the end. It is a mindset you adopt from the beginning. The best time to think about failure modes is during design, not during an incident.
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