That's bad news. On our server we do daily backups using heidisql. I export the auth char and emucoach world databases by right clicking and export as sql. And then that backup folder is copied to a second computer for safekeeping. I also check the drop create check boxes before exporting, Just in case i have to recreate those databases due to some hardware failure.
There are .bat files on the internet that will do this for you as well. Or cron jobs for linux.
These backups can use up a lot of space after a few months, So you have to clean them up every now and then.
Anyway, I hope you made backups. And all goes well.