System Design Card 451 — Resilience and Disaster Recovery / Breakdown
Concern
Resilience asks how the system degrades, recovers, and protects data when parts of it fail badly. Backup strategy, regional failover, replay, dead-letter handling, and controlled degradation all matter here.
What Breakdown means for this concern
In BASIC, the Breakdown step is where you clarify the product goal, workload shape, and non-functional requirement that will dominate the design. For Resilience and Disaster Recovery, that means the candidate should make this concern visible at the right moment instead of bolting it on at the end.
Design move
A good move is to split the problem before trying to solve it. Tie the concern back to the user flow, the workload, and the dominant trade-off. That keeps the design grounded and makes it easier for the interviewer to follow why a cache, queue, replica, partition, or rate limiter is actually necessary.
Common miss
The miss is assuming that ordinary redundancy automatically solves major fault scenarios. BASIC helps because the staged flow keeps this concern proportional to the prompt and connected to the rest of the architecture.
BASIC prompt
“When I reach the Breakdown stage, how does Resilience and Disaster Recovery change the architecture, the trade-offs, or the review checklist?”