分片可以与复制一起使用吗？

Question

Can sharding work with replication?

if they can how many servers do we need for a minimal setup?

if not, what is the best option for high availability?

Answer 1

Yes, it can. See second FAQ at http://docs.mongodb.org/manual/faq/sharding/

Depends on your needs: you can run a version of mongod with as little as a single server. I suppose the minimum to have both sharding and replication would be to have 2 shards each in a replica set of 2 servers.

Once again depends on your application and needs. How fault tolerant does your system need to be? Naturally more replicas will increase availability. Sharding only allows you to distribute your data/computations so that does not increase availability.