Amazon Aurora is a managed relational database that is compatible with either MySQL or PostgreSQL. You might be wondering why we have Amazon Aurora when Amazon RDS already supports MySQL and PostgreSQL. The keyword with Aurora is compatible—whereas RDS manages the full open source implementation of those databases, Aurora was built from the ground up using AWS storage technologies to offer databases that look and feel like MySQL and PostgreSQL to external tools and clients but offer improved performance and availability.
If you already have an application built on one of these open source databases running on-premises or in the cloud, you can safely migrate it to Aurora with no changes and enjoy a significant performance boost, along with automatic replication across three AZs.