linux/Apache/WHM-cPanel, shared server
customer has identical accounts on 2 sever, geografically different locations. mySQL db running
He wants that the 2nd account gets an update from the active account regulary, so that all on the 2nd account is identically and up to date always, and if there will happen a server problem or DNS problem on the first (active) account, that the 2nd account gets active automatically (and twisted). And both don't have data loss or lags.
You can't really do this "properly" just with two shared hosting accounts, the closest you could get would be to add secondry DNS for the backup/mirror server and make sure the TTL values for the domain are set very low (5 minutes or so)
If the first server then goes down, that's roughly how long most people would have to wait before they would start to see the new location, but for some, depending on their ISP they wouldn't get switched over and would just see the site down.
To do it almost seamlessly, like you asked, you would need a server cluster and some sort of load balancing.
To mirror the data you would need to setup a cron job using rsync.
You might remember me, I'm Alex-Info, we used to have the same provider (VS) and now again we have the same provider (RS)
Joe (RS) told me about your request, and asked me if I had something for you...
He said that you were more concerned about getting the database backedup regularly than having it "live" on another server. If that's the case, then my 'lil backup scrippt would do wonders for you. You can set it up to backup any database(s) and FTP them to a remote server, all automatically. This way, if your primary server crashes, you go on the second server, open phpMyAdmin to restore the last backup, and voilą !
Would that be okay ?
Or, if you need something more "live" (two databases in almost-perfect sync) I could code it from scratch, but that would be a new coding job ($).