I need a back-up solution for my data (~4TB). What do you recommend ? Now I save have all the data on a RAID 1 and no back-up but I think it's time for a back-up solution as one of the harddisks is not healthy anymore.
Get some 1TB USB External Drives. Then back up your data in them. That is all. Flash drives are normally single. So you would have to get at least 4 drives of 1TB or 2 drives of 2TB depending on your preference. Backing up data is a pain and i don't normally do it. Although i admit its a good thing to do from time to time.
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.
I forgot to type last I checked Microsoft Skydrive was the cheapest per gigabyte, but lacked features like automatic backup.
I use a program called Crashplan. I really love it. You can get unlimited backup to the cloud for 3 bucks per computer per month. You can backup to your own network for free. I'm not a salesman so Google it if you're interested.