架构师训练营第 6 周作业

CAP定理

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

简单翻译为：在一个分布式系统（指互相连接并共享数据的节点的集合）中，当设计读写操作时，只能保证一致性（Consistence）、可用性（Availablity）、分区容错性（Partition Tolerance）三者中的两个，另外一个必需被牺牲。



• 一致性：对某个指定的客户端来说，读操作能够保证返回最新的写结果

A read is guaranteed to return the most recent write for a given client.



• 可用性：非故障的节点在合理的时间内返回合理的响应（不是错误和超时的响应）

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



• 分区容忍性：当出现网络分区后，系统能够继续“履行职责”

The system will continue to function when network partitions occur.