Dag member server switch
Exchange 2013：
Exchange Management Center: Click Server
Choose your own needs in the following interface, I will choose the specified here
Just click save
The following is done
View the current main service server
get-mailboxdatabasecopystatus
Switch to another server and start the migration command
Move-activemailboxdatabase -server "server name"
After the migration is complete, this is the sign of the switch,
get-mailboxdatabasecopystatus 