Have you considered backing up your data to the cloud? At 4 TB you'll have to pay for the service. There is a toms hardware review here:http://www.tomsguide.com/us/cloud-storage-service-computing,review-1539-8.html
I would seirously consider this if you care about your data. A fire, theft, or accident at home and all that data is gone. If you want your data to be around 20+ years or so, you should consider some serious enterprise raid stuff with offsite backup, or a cloud based solution.