Managing failover in Amazon RDS

RDS instances can be Single-AZ or Multi-AZ. In Multi-AZ, multiple instances work together, similar to an active-passive failover design.

For a Single-AZ RDS instance, storage can be allocated for that instance to use. In a nutshell, a Single-AZ RDS instance has one attached block store (EBS storage) available in the same Availability Zone. This makes the databases and the storage of the RDS instance vulnerable to Availability Zone failure. The storage allocated to the block storage can be SSD (gp2 or io1) or magnetic. To secure the RDS instance, it is advised to use a security group and provide access based on requirements.

Multi-AZ is always the best way to design the architecture to prevent failures and keep the applications highly available. With Multi-AZ features, a standby replica is kept in sync synchronously with the primary instance. The standby instance has its own storage in the assigned Availability Zone. A standby replica cannot be...