In the case of a disaster, use Route 53 with the failover routing policy, since these servers are always using the primary active database that they will require to implement a fail-fast code strategy, to switch traffic to the new master database (warm passive standby). This can be done by catching connector exceptions in the code and using sensible timeouts. Scale horizontally, to accommodate for the current production traffic. In order to build resiliency, use multiple AZs.

Some of the relevant services are as follows:

• Elastic load balancing, with cross-zone load balancing
• EC2, with burstable capacity (t3 family)