Change the single node of Postgres database into master-slave

The phenomenon and background of the problem

Currently online postgres The database is in single node mode , To improve performance , Want to change master-slave ,
Data volume ：2t
Database version ：11.5

My solution ideas and tried methods

Because of the large amount of data , Ordinary methods cannot be realized ,
If you need to open any permissions ？ How to transmit data ？