Originally Posted by willdebeast
...I thought RAID 0 was a single drive working alone, and RAID 1 was two drives backing each other up. So why would RAID 0+1 be 4 drives total?
RAID 0 uses 2 drives where the data is stripped alternately across both drives. It's supposed to give a speed increase in read/write tasks but to be fair I will never think RAID 0 is worth the extra speed I might gain and you don't get data redundancy. I have nick-named it AID 0 because of the lack of redundancy in this array. Worthless i'd say although others will disagree.
RAID 1 array also uses 2 drives but the data is mirrored on both drives. What's on one drive is exactly mirrored to the other drive. RAID 1 and above are worthy of the title as RAID 1 and above have some kind of redundancy; if a disk/s fails the data is available on the other/s.
The other arrays use more drives and uses a mixture of both mirroring and alternate striping to increase redundancy.