If you have already RAID1 on server (provided) then it would be enough. Forget about it.
If you look for data storage solution with some fault tolerance, you should rather look for RAID5 solution. It gives you nice read performance and can survive one disk failure in a volume (in basic setup). http://en.wikipedia.org/wiki/RAID5#RAID_5
If you want to have all data accessible on demand, choose storage array which could be upgraded with expansion trays to extend storage space. If you have short data retention cycle you may drop that 1.2 TB onto tapes and reuse array's space. It also depends on required performance. If you want quick access, you should go for FC drives, if you want to cut costs and store data, consider SATA. Possibilities are countless.. You need to define your requirements and budget more granularly and then narrow areas of interest.