Chapter 12. Working with RDS Read Replicas

There are a variety of scenarios in which you might want to deploy read replicas for your read-intensive workloads. RDS uses built-in replication functionality in database engine such as PostgreSQL, MySQL, and MariaDB. Note that you cannot deploy read replicas for Oracle and SQL Server database engines. There is a maximum 6 TB size limit on MySQL, MariaDB, and PostgreSQL DB instances. If you want to scale beyond the compute or IO capacity for a single instance, a read-intensive database workload, then using read replicas is a solution. You can also redirect your reporting application to query from read replicas instead of the primary database. Running your reporting queries against read replicas will significantly improve the performance of your primary side. You can also plan to create read replicas in a region closer to your user, so that data locality can be implemented and latency can be reduced.

By default, read replicas are created with the...