We're in the process of migrating some websites from one of our older Windows Server 2003 / IIS 6 Servers to a newer Windows Server 2008 / IIS 7 server. We have to migrate these websites without a lot of downtime.
These websites all communicate with SQL Server and/or MySQL databases. They also have SSL certificates assigned to them (they're e-commerce sites).
Our initial plan was to stop the websites on the old server for a few minutes, copy over the websites and databases to the new servers, and redirect the IIS 6 sites on the old server to
www2.<domain>.com which points to the new server. This way traffic that still comes to the old server while DNS caches are flushed is redirected to the new server.
The problem with this is that the SSL certificates are for
www.<domain>.com and visitors see a security warning if they're on
www2.<domain>.com. It's important that all traffic be pointed to the new server immediately as we can't have 2 separate copies of the databases or websites.