1) the RAID is only 2 hard drive 1 TB.
2)To store information collect RAID 1, it will make a mirror from two screws, the final volume is 1 TB, and if one screw dies of old will be on the second.
3)in this RAID, the idea is you will win in speed, but slightly loses in the record.
4)don't buy raidcontroller, make a software RAID, a good raidcontroller 300 bucks you have not enough money, but the quality is worse than cheap liftovogo RAID.
5)Uminosity the one who wrote that RAID 0 is a mirror. Pruflink ru.wikipedia.org/wiki/RAID
6)When the current capacity of processors on your RAID 1 will take CPU resources quite a bit, for simple mirroring, without checksum(as in 5-th and 6-th RAID).
7)the System is put on the screw 250 and not to store any important data in addition, it will give a small performance boost.