I’m running my media server with a 36tb raid5 array with 3 disks, so I do have some resilience to drives failing. But currently can only afford to loose a single drive at a time, which got me thinking about backups. Normally I’d just do a backup to my NAS, but that quickly gets ridiculous for me with the size of my library, which is significantly larger than my NAS storage of only a few tb. And buying cloud storage is much too expensive for my liking with these amounts of storage.
Do you backup only the most valuable parts of your library?
Have you considered only backing up the data you can’t replace relatively easily? I would look into a strategy of periodically backing up the list of media in a format that can easily be imported into Radarr or whichever system you used to acquire them. Sure, if the worst happens it’ll take forever to redownload, but you can just prioritise the things you want to watch right now while everything’s rebuilding in the background.
Definitely do back up photos, documents and your home directory (excluding stuff like a steam library), but hopefully you should be able to fit all that on a NAS or external HD.