ZFS doesn't have a repairing fsck because it doesn't need one. The on-disk format uses a transactional design such that its always consistent, even if it fails

ZFS doesn't have a repairing fsck because it doesn't need one. The on-disk format uses a transactional design such that its always consistent, even if it fails in the middle of a write. AFIAK the only way to damage a zpool is if some snafu (one more serious than a mere write failure) wiped out a bunch of metadata together with the backup metadata all at the same time, but such an event would do very serious damage to any filesystem, which is why all important data should have an off-site backup.