This is the kind of question that sounds easy if you know the theory but they really want a real project, not a textbook answer.
Choose a concrete project where you had to make a deliberate trade-off between consistency and availability due to network partitioning. Structure your answer by first describing the system requirements and constraints, then explaining the CAP trade-off decision, and finally detailing the implementation and its impact on the business. Emphasize how you measured and validated the trade-offs.
Pro tip: Netflix prioritizes availability and partition tolerance (AP) for most user-facing services, so highlight how you optimized for availability while managing eventual consistency. Show that you understand the business impact of your choices, not just the technical details.
Briefly describe the project, its goals, and the specific requirements that forced you to consider CAP theorem. Mention the scale, user impact, and any constraints like latency or data consistency needs.
Explain which two of Consistency, Availability, and Partition Tolerance you prioritized and why. For Netflix, often AP is chosen, so discuss how you handled eventual consistency.
Detail the technical decisions: data stores used (e.g., Cassandra, DynamoDB), replication strategies, conflict resolution, and how you ensured the system remained available during partitions.
Explain the consequences of your choice, such as stale reads or write conflicts, and how you mitigated them (e.g., read-repair, versioning, compensating transactions).
Conclude with the results: improved availability, user experience, or business metrics. Reflect on what you would do differently and how it shaped your understanding of distributed systems.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.