5 / 6 The Tradeoff Vocabulary

Beyond the Three Letters

A team runs a single-region cluster with quorum reads and writes across three availability zones. There are no network partitions, yet they still argue about whether reads may come from a single nearby replica. A senior engineer says CAP is the wrong frame for this argument. Why?

A

CAP is a statement about durability rather than reads, so it governs write acknowledgement settings and says nothing about any read path

B

CAP does not apply to clusters with an odd replica count, since quorum majorities make the availability side of the tradeoff unreachable

C

CAP applies only across regions, because availability zones share one failure domain and therefore cannot be partitioned from one another

D

CAP binds only during a partition; with the network healthy the tradeoff is consistency against quorum latency, which is what PACELC names