Every database you create can be created on db optimized instance types such as db.t2, db.m4, db.r4, and so on, depending of the database engine chosen. The storage type can be general purpose SSD and provisioned IOPS, which is the recommended option.

The allocated storage starts with a minimum of 100 GiB and a maximum of 16 TiB. Customers have the option to increase the storage or, change the underlying storage type.

Database objects are created on database instances. Think about security and stability for all RDS customers, having the ability to update and upgrade every single database instance in a consistent way. To achieve that kind of control, AWS has to take full control of every layer to run the database engine, this is why privileged access to the operating system is limited. Nevertheless, customers have the ability to fine-tune and configure their engines though parameter groups.