How should the actual capacity of the various RAID groups be calculated?

Failure Phenomenon:

How should the actual capacity of the various RAID groups be calculated?

　Solution:

1, RAID 0 (striped disk Array without Fault tolerance): RAID0 all hard drives in parallel, capacity is the sum of all hard disk capacity, and hard disk access speed depends on how many hard drives, when the number of hard drives RAID The faster the 0 array access rate is, the greater capacity efficiency is the highest in all raid groups, with a capacity utilization of up to 100%.

2. RAID 1 (mirroring) RAID 1 hard disk mirroring backup operation is set by two hard drives, its primary hard disk another mirrored hard disk main hard disk data shutdown image Another mirror, the hard drive due to the main hard disk data to stop mirroring RAID 1 high redundancy, and capacity due to the loss of mirrors, only the original total capacity of 50%. (In addition, RAID 1 supports only two hard drives, and the maximum capacity is the capacity of a disk.) )

3, RAID 5 (Striping with distributed parity): RAID 5 fault Tolerant average distribution on the hard drive, when one of the hard drives fails, you can ensure that the other members of the hard disk data is normal, so the total capacity of the RAID5 is "(N-1) * Minimum capacity hard disk capacity ", for the overall, RAID5 capacity efficiency is higher, in all array neutral price is relatively good, so the mainstream raid group mostly use RAID5 array.