Amazon’s cloud DNS failover new feature
Amazon’s Route 53 new DNS Failover feature gives you high availability functionality without the need of deploying complicated and expensive solutions. You can monitor your website and automatically route your visitors to a backup site if it goes down.
With DNS Failover you can create a simple, low-cost, and reliable way to deploy a backup website.
‘Of course no one wants their site to go down, but things happen, whether due to deploying bad code, network outages, or other issues, and it’s helpful to have a backup which gives your customers a good experience in the event that your primary website does go down.’
Read more here - http://aws.typepad.com/aws/2013/02/create-a-backup-website-using-route-53-dns-failover-and-s3-website-hosting.html