[corney91]

I agree it's very good, and I use it for a lot of other folders eg notes, but I don't see how to use it as a backup tool for photos, without either using the option linked above or copying/hardlinking elsewhere on the NAS end. Unless there's a setting I'm missing that stops it from deleting on the NAS end?

EDIT: Don't get me wrong, it's my favourite file syncing tool, especially as one of the few open source syncing solutions. But I worry it always gets recommended as a backup tool and people don't realise it'll also sync deletions, so they'd suffer data loss.