Operation Scenarios
In the case that the load of the read operation of your application is much greater than that of the write operation, and read IO suffers too much stress, you can consider creating a read-only instance to balance the load of the read operation on the active database.
Operation Steps
1. Log in to the Console.
2. Click 
in the upper left corner of the Console and select a Region and a Project.
3. Select Database > RDS MySQL. Enter the RDS Console.
4. On the Instance Management page, select the specified instance, click More and select Create Read-only to go to the Create Read-only interface. You need to select the basic configuration, data storage space, and quantity of the read-only instance.