Correct. Backing up a corrupt database is wrong and we should neve have done it, and we don’t do it anymore.
No. There are some leveldb repair tools out there, but they basically are only fixing index errors, and in our experience, that’s not usually the case in our world.
In the 2 cases noted above, non-reversible damage has occurred. If the bits on the disk were modified or files were deleted, there is no recovery possible. That’s why we suggest backups and have built backup functionality into the core system. Unfortunately, pre-880 backups may also have saved corrupt databases because of that unfortunate lack of integrity check pre-backup.