Automated maintenance notices can save the day for your site when all else has failed. While the requested page is not delivered, a page explaining the situation is a much better response than nothing at all. The user then knows that the site is still active and they can expect it to be available shortly.
In the event of a hardware or network failure it is imperative that the maintenance notice be hosted on a separate server and network. It is impossible for unreachable servers to deliver notices about their own status.
edgedirector clients are provided with an automatic maintenance notice facility. In the event that the server health monitoring system determines that there are no servers to provide the requested resource, answers to dns queries will be given that point the client at a notice page hosted on edgedirector servers.
The mechanism has been carefully designed to avoid confusing search engines that happen to request pages during an outage event.
Note that it is also possible to use a low cost independent server such as a VPS as a failover site. The site need not be a full replica of the main site because its main purpose is to serve as a standby site when the main site is not available.