aws ElastiCache for reids basic
术语说明
复制组
- replication Group： shards implement replicaton by 1 node as read/write Primary and up to 5 other nodes as read-only replicas
- replication Group：A Redis (cluster mode disabled) replication group is a collection of clusters, where one of the clusters is a read/write primary and the others are read-only replicas. Writes to the primary are asynchronously propagated to the replicas.
- 自己的理解，replication group 即 复制组，之所以是一个集群的集合，节点=cache cluster，这一点在下边的文档里写了，但是单节点集群是不能叫做复制组的，因为他只有一个节点，这个节点可以叫“cluster”
- 复制组本身是一个仅在命令行级别存在的概念，从控制台看到的都叫集群，每一个节点组都叫做分区具体参考下边这个图片 和文档链接
https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/WhatIs.Terms.html
- cluster： A Redis cluster is a logical grouping of one or more ElastiCache for Redis shards. Data is partitioned across the shards in a Redis (cluster mode enabled) cluster.
非集群模式
- 一个分片最多6节点 1主5复制
- 始终只有1个分区
集群模式
- 最多90分片，每一个最多6节点，所以可以有15个主节点加
