Support for Multi-AZ deployments was announced in May 2010. [19] Relational Database Services Multi-Availability Zone (AZ) allows users to automatically configure and maintain synchronized physical or logical "standby" replicas in different Availability Zones [20] (independent infrastructure in physically separated locations), depending on the database engine. A Multi-AZ DB instance can be created for development or modified to run later as a Multi-AZ deployment. Multi-AZ deployments are designed to provide enhanced availability and data durability for MySQL, MariaDB, Oracle, PostgreSQL, and SQL Server[21] instances and are targeted for production environments. [22] In the event of planned database maintenance or an unplanned service outage, the relational database service automatically fails over to the latest standby database, allowing database operations to resume without administrative intervention.

A Multi-AZ relational database service instance is optional and has costs associated with it. When creating a relational database service instance, the system will ask the user whether to use a multi-zone relational database service instance. In a Multi-AZ Relational Database Service deployment, backups are done in the standby instance, so I/O activity is not paused at any point, but users may experience increased latency of several minutes during backups.

Pricing for relational database service instances is very similar to Elastic Compute Cloud (EC2). Relational database services are billed by the hour and come in two packages: On-Demand DB Instances [29] and Reserved DB Instances.