backups

I am thinking of building a NAS with the bits of an old PC that have lying around, but I don't intend to use it like a NAS in terms of leaving it on all of the time. Rather, I am intending to use it for hosting my Jellyfin shows/movies and for backing up my photos. So it will only be turned on...

I am hoping some of you may be able to help me. I recently had a backup fail on a hard drive and it appeared the partition on the backup drive was corrupted. I therefore tried to sort it out, but somehow (and I still don't know how) I managed to delete the partition on my primary images disk...