In a multi-site architecture, there are multiple production environments running in active-active configuration on AWS only or a hybrid of on-premise and AWS cloud infrastructure. In cases of disaster, the traffic is routed to the already running alternate sites. You can use the weighted routing feature of Route 53 for this purpose. You will need to ensure sufficient capacity at each site, or a rapid scale up of capacity as provided by the auto-scaling feature on AWS, to avoid poor customer experience or cascading failures from occurring. The costs associated with this option depend on how much production traffic is handled by AWS during normal operations and at peak loads.