raid10 and raid01
RAID 0 over RAID 1(raid 0+1, raid 10, stripe of mirrors, better)
(RAID 1) A = Drive A1 + Drive A2 (Mirrored)
(RAID 1) B = Drive B1 + Drive B2 (Mirrored)
RAID 0 = (RAID 1) A + (RAID 1) B (Striped)
RAID 1 over RAID 0(raid 1+0, raid01, mirror of stripes)
For write performance: raid0 > raid10 > raid5
For read performance: raid1
For data protection: raid1
Raid2 - put parity data into multiple disks. stipe using bit/byte
Raid3 - put parity data into single disk. Good for sequential data, but for random data, parity disk will become bottleneck. stipe using bit/byte
Raid4 - put parity data into multiple disks. stipe using block/record.
Raid5 - put parity data into all disks. Good for small/random access. write punishment(one write will generate two reads for old parity/data, two writes for new parity/data)
Raid6 - added another parity data. Can tolerate two disk failing. Worse write punishment.