4. 什么是Hash
Wikipedia: A hash function is any function that can be
used to map data of arbitrary size to data of fixed size.
The values returned by a hash function are called hash
values, hash codes, digests, or simply hashes.
哈希函数就是能将任意长度的数据映射为固定长度的
数据的函数。哈希函数返回的值被叫做哈希值、哈希
码、散列,或者直接叫做哈希。
13. 一致性哈希(Consistent Hashing)
Karger 等人1997年提出
Consistent Hashing and Random Trees: Distributed
Caching Protocols for Relieving Hot Spots on the World
Wide Web
Web caching with consistent hashing
几个关键概念
Balance(均衡性)
Monotonicity(单调性)
Spread(分散性)
Load(负载)