It allows you to have a read-only copy of your production database. This is achieved by using Asynchronous replication from the primary RDS instance to the reach replica. You use read replicas primarily for very read-heavy database workloads.
Relieve pressure on your source database with additional read capacity
Bring data close to your applications in different regions
Promote a Read Replica to a master for faster recovery in the event of a disaster
Upgrade a Read Replica to a new engine version
Supported for MySQL, MariaDB, and PostgreSQL