一致性哈希算法(Consistent Hashing Algorithm)是一种分布式算法，常用于负载均衡。Memcached client也选择这种算法，解决将key-value均匀分配到众多Memcached server上的问题。它可以取代传统的取模操作，解决了取模操作无法应对增删Memcached Server的问题(增删server会导致同一个key,在get操作时分配不到数据真正存储的server，命中率会急剧下降)，-Consistency hash algorithm (Consistent Hashing Algorithm) is a distributed algorithm commonly used in load balancing. The Memcached client also choose this algorithm to solve the key-value evenly distributed to many Memcached server. It can replace the traditional modulo operation modulo operation can not cope with the additions and deletions Memcached Server (additions and deletions server will result in the same key, get operations allocated less than the real data storage server, the hit rate would drop dramatically)