Not the parent, but my homebrew backup script first makes the backup and then attempts to restore a canary file. If that fails it raises the alarm. It's not pe

Not the parent, but my homebrew backup script first makes the backup and then attempts to restore a canary file. If that fails it raises the alarm. It's not perfect. I can imagine a scenario where the canary is restorable, but some other important files aren't. However it certainly protects against cases where a bug in the backup software makes a completely unreadable snapshot (which has happened to me before).