Selecting a RAID level and tuning performance

Disk arrays are used to improve performance and reliability. The amount of improvement depends on the application programs that you run on the server and the RAID levels that you assign to the logical drive.

Each RAID level provides different levels of fault-tolerance (data redundancy), utilization of physical drive capacity, and read and write performance. In addition, the RAID levels differ in regard to the minimum and maximum number of physical drives that are supported.

When selecting a RAID level for your system, consider the following factors.

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RAID level	Data redundancy	Physical drive capacity utilization	Read performance	Write performance	Built-in spare drive	Min. number of drives	Max. number of drives
RAID level-0	No	100%	Superior	Superior	No	1	16
RAID level-1	Yes	50%	Very high	Very high	No	2	2
RAID level-1E	Yes	50%	Very high	Very high	No	3	16
RAID level-5	Yes	67% to 94%	Superior	High	No	3	16
RAID level-5E	Yes	50% to 88%	Superior	High	Yes	4	16
RAID level-5EE	Yes	50% to 88%	Superior	High	Yes	4	16
RAID level-6	Yes	50% to 88%	Very High	High	No	4	16
RAID level-00	No	100%	Superior	Superior	No	2	60
RAID level-10	Yes	50%	Very high	Very high	No	4	16
RAID level-1E0	Yes	50%	Very high	Very high	No	6	60
RAID level-50	Yes	67% to 94%	Superior	High	No	6	60 (SCSI) 128 (SAS, SATA)
RAID level-60	Yes	50% to 88%	Very High	High	No	8	128
Spanned Volume	No	100%	Superior	Superior	No	2	48
RAID Volume	No	50% to 100%	Superior	Superior	No	4	48

Physical drive utilization, read performance, and write performance depend on the number of drives in the array. Generally, the more drives in the array, the better the performance.