架构师训练营第 06 周—— 练习

请简述 CAP 原理。

In a distributed system (a collection of interconnected nodes that share data.), you can only have two out of the following three guarantees across a write/read pair: Consistency, Availability, and Partition Tolerance - one of them must be sacrificed.

https://robertgreiner.com/cap-theorem-revisited/

一致性（Consistency）：A read is guaranteed to return the most recent write for a given client.

可用性（Availability）：A non-failing node will return a reasonable response within a reasonable amount of time (no error or timeout).

分区容忍性（Partition Tolerance）：The system will continue to function when network partitions occur.

虽然 CAP 理论定义是三个要素中只能取两个，但放到分布式环境下来思考，我们会发现必须选择 P（分区容忍）要素，因为网络本身无法做到 100% 可靠，有可能出故障，所以分区是一个必然的现象。