ON can sync off of a regular old file share. I've been using it for years. A copy on our server and one on each of my computers (desktop, laptop, Mac) and they all happily sync up. Granted, the iPhone app works best with OneDrive. I'm not a fan of OneDrive and use DropBox instead for a smaller ON notebook that I share with my wife for things like handy pictures of our insurance cards, grocery lists, travel information, etc. Works great for us at work (documentation and pictures) and at home.