How will migration handle corrupted files or other files that should not be there?
As reported I saw the issue that corrupted pieces from blob folders got successfully moved to the trash by retain process. But the trash deleter obviously did not delete them but errored and made the deletion quit which in my opinion should not happen. Anything in the trash should be deleted regardless if it is a valid piece or not.
So what will happen if the migration process stumbles across e.g. corrupted pieces?