Looking at our service, now that it's using RethinkDB, we can have the best of both worlds and enable sharding and replication at the same time. Head to the Administration Console and click on the Tables tab at the top:
Click on our images table and scroll down:
You can see that our table is on one shard (the default), with only one replica per shard. Down the bottom, you can see the server (blue link) on our cluster that is holding the table. Click on Apply configuration:
You can configure the number of shards and ...