consistent hashing

When you shard a vector index or route requests across model replicas, naive 'hash mod N' reshuffles everything the moment N changes. Consistent hashing moves only a small fraction. Here is the implementation.

The Dynamo question. Interviewers want three decisions made cleanly: how you partition keys so adding nodes does not reshuffle everything, how you replicate for durability, and where you sit on the CAP spectrum. Here is how to reason through all three with concrete quorum math.

A cache is easy until you spread it across many nodes. Then come consistent hashing, eviction policy, the thundering herd on a cache miss, hot keys, and how much staleness you can tolerate. Here is the design that holds up under real traffic.