Sounds like where and how you are hosted has metered traffic/bandwidth and the max is such that a large backup hits the limit that results in a corrupted 500 MB file.
So how are you hosted and what are the limitations of that hosting? shared hosting very cheapo package?
Yeah, can't do automated backups probably, but ...
what if one were to manually go into a course and backup but during the entire backup process select only say the first 2 sections of the course. Might have to make 2 or 3 backups of the same course only with different sections - 2nd backup has only section 3 and 4, 3rd backup as only section 5 and 6.
Basically breaking up backups to produce a backup mbz file size smaller than the limit. Pain in the arse!
So where you are hosted can you increase limitations (that's not inside Moodle)?
'SoS', Ken