MediaFire was designed to let people host files and images to share with others. It was not meant to be used as a backup service.

Although we store at least 2 copies of every file you upload, we do not recommend that you use it to backup unique copies of files that cannot be replaced if they should become inaccessible on MediaFire for any reason.

If you're looking for a service to back up files (but not host them), we recommend using Mozy. Mozy offers 2GB of disk space for free or unlimited disk space for only $4.95 per month.