Linearizable reads see the latest write — at a cost.
Strong Consistency Models: linearizable reads see the latest write
choose the failure mode you can explain
Linearizable lock has ~5–20ms acquire latency cross-zone.
Linearizability is the strongest practical consistency: every read sees the most recent committed write, system-wide. It's expensive — every operation conceptually crosses every replica — but is required for correctness in some workloads (locks, balances, coordination).
Linearizable: total order, real-time ordering matches.
Sequential: total order, but doesn't guarantee real-time order across processes.
Implementations: single-leader with synchronous quorum, or consensus protocols (Paxos, Raft).
Most user-facing apps don't need it; finance, locks, leader election, configuration do.
Distributed lock for daily report generation.