I think it’s useless since, as @Arkina explained it, Storj is a decentralized storage network and already takes care about redundancy.
But of course, you might want to have redundant hardware for your own interest (i.e.avoid being disqualified). In this case, a such sync is not really a good solution since your node may be disqualified at the time your disk fails. Even if you have a backup, your node may be already disqualified.
If you really want to secure your hardware, setup a RAID (RAID1 or RAID5 or something like that but not RAID0). It is like an “insurance” fee since your extra hardware could actually be used to store data (and generate more earnings) instead of “backing up” an existing node.
It’s a question of trade-off.