What "Concurrent" Actually Means
Why concurrent writes survive even a strict quorum, why last-write-wins is only safe for keys you never rewrite, and why two operations minutes apart can still be concurrent.
#leaderless
The Limits of Quorum Consistency
Why w + r > n is a probability dial rather than a guarantee — the edge cases that return stale data anyway, the consistency guarantees quorums never provide, and why staleness is so hard to monitor.
Sloppy Quorums, Hinted Handoff, and Multiple Datacenters
What a leaderless database does when a client cannot reach its quorum at all — why the fix buys durability rather than consistency, and how the same model stretches across datacenters.
Version Vectors, Siblings, and Tombstones
How a database tells an overwrite from a conflict — the version-number algorithm behind siblings, why merging by union resurrects deleted items, and what a version vector adds once there is no single replica.
Leaderless Replication
How Dynamo-style databases let any node accept writes, tolerate node failures without failover, repair stale replicas through read repair and anti-entropy, and tune the quorum condition w + r > n.