I am in the process of migrating a replica set from a data center to AWS, but when I checked the settings, I noticed that the Sharding is not enabled, yet they are using 3 MongoS / Routers and 3 MongoC / Config servers - So since Sharding is not used in the current system, would it be safe to migrate the replica sets and not use MonogoS nor MongoC ? Can the users connect directly to Mongo database replica set without using MongoS ?
Or should I use at least 1 MongoS and 1 MongoC config server ?