Balance Backend Availability, Maintainability, and Scalability

How would you improve the availability, maintainability, and scalability of a distributed backend service? Explain how you would choose among changes when the goals compete. ### Constraints No traffic volume, data consistency requirement, or availability target is supplied. State the requirements you would clarify before selecting an architecture. Use one explicitly hypothetical service example to make the tradeoffs concrete; do not assume every service needs global deployment or microservices. ### Clarifying Questions - Which user operations are critical, and what failure or latency targets must they meet? - What growth is expected, and which resource or dependency currently limits capacity? - What team size, deployment process, and maintenance burden constrain the design? ```hint Make the tradeoff measurable Adding replicas can improve capacity while creating consistency and operational costs. Identify both the intended benefit and the new obligations. ``` ### What a Strong Answer Covers - Concrete measures for each of the three goals and requirements that guide them. - Dependency failures, capacity bottlenecks, and operability of the proposed design. - A justified sequence of improvements and a way to verify their effects. ### Follow-up Questions - When could a simpler deployment improve availability more than adding another service? - How would you prevent autoscaling from overwhelming a shared database?