Keep your web shop open with Simple Failover.
Simple Failover is a new software based failover solution.
The concept really is simple; it continuously monitors your servers to find out which are up and which are down, and then it dynamically updates your DNS records accordingly so that your domain name always points to a functional server.
DNS records are updated directly via the DNS protocol (optionally using encrypted signatures for security), via WMI, via HTTP based dynamic IP updates, or via custom scripting.
It can also send you e-mail notifications when problems are detected, and it can be extended through scripting to provide custom notifications, logging, and data capture.