Why couldn't you just resell the 2TB drive (after doing your best to completely format it of course)? That would already recoup some of the costs of a 4TB drive. Also with the cloner you'd have to buy another 4TB drive as the actual backup device. But I'm wondering if this is needed at all. Like if your 4TB dies one day and you lose all your data for your validator, don't you still own the keys to set the "validator software components" up again from a fresh start? The penalty for being offline for a few days is no big deal. Of course a backup is always good. But you might as well go with a different backup strategy where every so often you back up your 4TB SSD to a 4TB+ HDD that is not nearly as expensive. The first backup might take quite long, but subsequent backups would only have to change files that have actually changed. That's just in theory when I think about software like Timeshift.