Maybe a question is when is it safe to start accessing the cluster through the mongos?
I just attempted to deploy the sharded cluster. I added the shard and the balancer started working. Only a single shard so I'd hope there wouldn't be much but I guess it has to build an index? I did some small tests and even though the balancer was still running I could access data through the mongos so I turned on my clients. The clients worked fine for about 10 minutes and then the mongos seemed to have just froze. Even after I stopped the clients mongos was still showing more than 20k open connections (which shouldn't have been this high to begin with).
Do I need to let the balancer completely index the data before I start accessing it through the mongos?
At what point is it no longer recommended to access through the mongod?