With RDS Aurora, any of your read replicas can be promoted to read/write master in the event of a failure of your primary master. This happens in 10-15 seconds

With RDS Aurora, any of your read replicas can be promoted to read/write master in the event of a failure of your primary master. This happens in 10-15 seconds, and is very fast. So, you can get the benefit of up to 15 read replicas, and not have to pay for an extra standby server that is sitting idle.