Amazon Aurora is a fully-managed, MySQL-compatible, relational database engine that combines the speed and availability of high-end commercial databases with the simplicity and cost-effectiveness of open source database (read my post, Amazon Aurora – New Cost-Effective MySQL-Compatible Database Engine for Amazon RDS , to learn more).
Aurora allows you create up to 15 read replicas to increase read throughput and for use as failover targets. The replicas share storage with the primary instance and provide lightweight, fine-grained replication that is almost synchronous, with a replication delay on the order of 10 to 20 milliseconds.
Additional Failover Control
Today we are making Aurora even more flexible by giving you control over the failover priority of each read replica. Each read replica is now associated with a priority tier (0-15). In the event of a failover, Amazon RDS will promote the read replica that has the highest priority (the lowest numbered tier). If two or more replicas have the same priority, RDS will promote the one that is the same size as the previous primary instance.
You can set the priority when you create the Aurora DB instance:
This feature is available now and you can start using it today. To learn more, read about Fault Tolerance for an Aurora DB Cluster .