Consider the Perfect OpenSuse 10.2 with ISPConfig for all the software that I am operating.
I have that server at a co-location facility and another server at a different facility for more security in the network and for DNS pursposes. I manage all my own DNS, so to be properly compliant with the IETF requirements, the servers are geographically separated.
One server should be the primary (master), and the other server the secondary (slave). And I wish to use them in as much of a failover capacity as possible. If the primary fails, I want the secondary to take over. This means that the secondary either needs replication of mysql, bind, apache, or whatever can be replicated, or it has to have a backup of the primary stored on it so that I can restore as much of the directory structure to it as possible. This will keep my users operational until I am able to repair the primary.