Pretend everything before 1.4 does not exist. I am terrible. (forgot to set it so the mod wasn't required on clients)
BTFU is a backup mod designed to be so easy and efficient, you'll have no excuse not to take frequent backups. When you install it, it will refuse to let your server run until you configure a backup directory. Past that, it will operate in the background without bothering you again, until the fateful day when you need to restore. BTFU backups are dead-simple to restore, because they're simply complete copies of your minecraft server directory. And BTFU takes these backups every 5 minutes, and yet is very easy on your disk space!
How does this sorcery work? BTFU implements a time-honored UNIX backup strategy. It uses rsync to sync your server state to a master backup copy, and then makes a hardlinked copy of that to a datestamped folder. Hardlinks are files that point to the same underlying data on disk. Because of this, each new backup takes up only as much space as however many files have changed since the last one. In other words, backups of your 5GB world don't take 5GB each, unless the whole dang thing is chunkloaded. Even then, infinitely many backups could take their toll, so BTFU lets you set a total limit (default 128) and will prune the backups logarithmically, meaning that it will keep a higher density of more recent backups, but will always retain the original backup and a complete history of your world. (You can also manually delete any backups you wish, and BTFU will not mind.)
BTFU wants you to relax. The reason for this backup approach is threefold:
Backups are very fast, allowing them to be taken continuously
Backups are incremental, allowing many to be kept with low disk space cost
Backups can be treated as copies of the server directory, allowing you to easily hand-restore the entire server, world, configs, mods, .mcregion files, or whatever else you want, or use tools like the wonderful mc-region-fixer to restore individual corrupted chunks
Once you configure your backups directory, you can forget about BTFU until something goes wrong. If it has issues taking a backup, it will print log messages. Otherwise it will stay quiet and do its job.
Using BTFU is NOT necessarily a complete backup strategy! There are two major threats to your world. This mod is here primarily to defend against world corruption from buggy mods or other issues. The other threat is underlying issues with your disk or filesystem. If you want BTFU you to defend against those, then it is up to you to ensure your BTFU backups directory is on a separate disk. It should go without saying that backing up to a folder right next to the server folder, won't help if that hard drive dies.
One more thing. The only way to get perfectly consistent backups is to fully shut down the server first. For example, say some player deposits an item from mod-based storage into a vanilla chest right before a backup, and the mod doesn't respect the save-all command. The resulting backup might have that item duped, because it exists in both the synced chest and the old un-synced version of the mod's storage. These issues are not likely to be a serious issue or hose your server, but the possibility is something to be aware of. Even if you use BTFU, it might also be good to occasionally shut down your server and take an offline backup. Personally, I don't bother. Up to you.