System Design Card 455 — Resilience and Disaster Recovery / Check
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 Check means for this concern
In BASIC, the Check step is where you review the design for bottlenecks, failure modes, security gaps, observability, and cost. 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 review and stress-test before you hand the answer over. 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 Check stage, how does Resilience and Disaster Recovery change the architecture, the trade-offs, or the review checklist?”