If you want to back up your MySQL database, you may want to do something other than just copying the file. If the database is active, there may be transactions that have not been flushed, and there may be tables in the file that aren't consistent with one another because of something that's in process.
One possibility is to use Zmanda Recover Manager (ZRM) for MySQL. You'll find links at
http://www.linuxquestions.org/bookmarks/tags/backup
