I'm going to have a co-located server running linux/apache/mysql and a local server with the same setup. The local will not be attached to the WAN, and the co-located will be accessible through a webapp.
I'm planning on having a database that will hold user accounts with passwords. This will be used for the remote webapp, and also for a local software package. The problem is that if the remote server dies for some reason, or is in-accessible, the local software will have no database to check for credentials.
So I am planning on having a server on the local side that syncs with the remote mysql database, but I'm not quite sure of the best way to handle this. Should I be running queries on both simultaniously? Does mysql have a way of handling this type of redundancy? What's the most secure way? What's the fastest way?