good idea but probably overkill. i only keep a handful of in-progress reads in CC library. i'ts calibre itself that gets the full-on paranoia triple backups approach. the worst that can happen on-device is that i lose last page read in up to 10 books , but that info is not in CC anyway ( yet, but I think you've stopped taking requests for that feature
)
i think I will shift the library to my actual Sd card, if only because moon+ telling me that the my files path is /sdcard/.. when its actually in internal storage is so annoying.