4TB probably forces you to have multiple hard drives, any of which will fail at any moment.
Maybe your best software bet is to use #git-annex assistant.
see the video, it shows how it works: it manages your files and puts them in several places of your choice, according to certain rules (for example, have at least 2 copies of each file in different locations). It’s all free software and there are no tricks, so if for some reason it’s broken, your files will still be available by other means.
Then you’ll have to do some maths to know how much it’s going to cost.
If you have your own hard drives, you must set them up with #RAID, and an off-site #backup, which means you need at least 500€ of hard drives. You’ll have to replace them once in a while, because they fail. Also, add in electricity :^)
In the cloud:
– If you use #Gandi_Simple_Hosting, you’ll need 4 instances that each costs 186,52 €/month
– With #OVH_Cloud_storage ( ▻http://www.ovh.com/fr/cloud/stockage ), you’ll pay something like 360€/month.
– If you choose #Amazon_S3 to store the data, it will cost about the same: 440$/month.
– A much better option financially is to store your data on #Amazon_Glacier ; it will cost you “only” 44$/month ( ▻http://aws.amazon.com/fr/s3/pricing ); it’s probably an excellent option for backup, but you have to know that it is very slow when you need to retrieve a file.
Also, if you want to share files with people, or look at your photos through a website, you’ll probably need another system, just for that. This system would only need to have the database of your files, and thumbnail images, and know how to communicate with the large storages. This, in terms of hosting, is cheap. But it will need a little programming.