I have a cluster with 12 servers. they all running mongodb 3.4.4, and use wiredtiger engine.
The structure is:
3 servers make one replica set. There are three of these.
3 config server for these 3 replice set.
1 mongos connection with all config server and listen on port 27017

There are 2TB data on the database. We occasionally power off, so I have to turn off the servers before the power turns off! I shutdown mongoDB service use "mongod --shutdown" on all servers and success, But when I restart the mongoDB service, they all failed!!!, log display the fail reason is "xxxxxxxx.wt is not found", after several failures, I know something wrong, and google it. I found this:
1. stop ballancing
2. shutdown mongoses services
3. shutdown config mongod services
4. shutdown shards mongod services

Is that right? I think that's right! But how to do?
sh.stopBalancer() #when restart, enable again?
sh.shutdownServer() # it's same as "mongod --shutdown"?

I need some guides. thank you