mongodb 副本集能否方便的扩展为分片的方式而不用停机？
分片的方式用的机子有点多，能不能做一个副本集使用，到需要分片来提高性能的时候再建立多个副本集，然后使用路由，控制服务器组成分片的集群？
ringa_lee2017-04-26 09:03:52
Yes.
See the official tutorial here: Convert a Replica Set to a Replicated Sharded Cluster
The prerequisite for smooth migration is to have a config server and all requests go through mongos. Since the subject already has a replica-set, the prerequisites are already met, so there should be no problem with smooth expansion.