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RAID level summary

Compare RAID levels according to their capabilities.

The following information provides data redundancy, usable disk capacity, read performance, and write performance for each RAID level.

Table 1. RAID level summary
RAID level Data redundancy Usable disk capacity Read performance Write performance Min/Max devices per array
RAID 0 None 100% Very good Excellent 1/18
RAID 5 Very good 67% to 94% Very good Good 3/18
RAID 6 Excellent 50% to 89% Very good Fair to good 4/18
RAID 10 Excellent 50% Excellent Very good 2/18 (even numbers only)
RAID 0
Does not support data redundancy, but provides a potentially higher I/O rate.
RAID 5
Creates array parity information so that the data can be reconstructed if a disk in the array fails. Provides better capacity than RAID level 10 but possibly lower performance.
RAID 6
Creates array "P" and "Q" parity information so that the data can be reconstructed if one or two disks in the array fail. Provides better data redundancy than RAID 5 but with slightly lower capacity and possibly lower performance. Provides better capacity than RAID level 10 but possibly lower performance.
RAID 10
Stores data redundantly on mirrored pairs to provide maximum protection against disk failures. Provides generally better performance than RAID 5 or 6, but has lower capacity.
Note: A two-drive RAID level 10 array is equivalent to RAID level 1.