Design a replicated key-value store with quorums

Design a distributed system that replicates key–value pairs across multiple replicas.

The interviewer wants to focus on replication, quorums, and failure handling.

Specify:

• APIs (e.g., Get(key), Put(key, value)), consistency goals, and assumptions.
• How data is partitioned and replicated.
• Quorum read/write rules (e.g., N/R/W) and how they affect consistency/availability.
• How you detect and recover from bad nodes, network partitions, and replica lag.
• Handling conflicts (if writes can be concurrent).

Keep it high-level but concrete enough to reason about correctness and trade-offs.