Amazon Route 53 performs health checks of the Amazon S3 service itself in each AWS region. When you enable Evaluate Target Health on an Alias record pointing to an Amazon S3 Website bucket, Amazon Route 53 will take into account the health of the Amazon S3 service in the AWS region where your bucket is located. Amazon Route 53 does not check whether a specific bucket exists or contains valid website content; Amazon Route 53 will only fail over to another location if the Amazon S3 service itself is unavailable in the AWS region where your bucket is located