Key-value store

How this question breaks down

1. 1ModelCore20 minTwo verbs, opaque bytes and a key that decides everything: the contract a distributed key-value store offers and what it gives up to scale.
2. 2Consistent hashingCore20 minPlace keys on a ring of hash values so that adding or removing a machine moves only its share of the keys, and give every machine many small tokens so the shares come out even.
3. 3QuorumsCore19 minStore every key on N nodes chosen from the ring, let a node on that list coordinate each request, and decide per request how many replicas must answer before it counts.
4. 4VersioningCore23 minTag every write with a vector clock so the store can tell "this replaces that" from "these happened at the same time", and hand the second case to someone who can merge it.
5. 5Anti-entropyCore21 minHow replicas agree again after drifting apart: hints replay the writes a down node missed, read repair fixes what a read notices, and Merkle-tree comparison finds everything else without shipping the whole dataset.

Work through the parts in order and you’ve covered the full design. Each part is one topic.