RAID Common level comparisons

comparison of RAID common levels

	Characteristics	Hard disk and capacity	Performance and safety	Typical applications
RAID 0	Used for parallel storage, that is, strips. The principle is to divide the continuous data into several pieces and then distribute it to each hard disk in the array. Any one disk failure will result in data loss.	Number of hard disks: one or more Capacity: Total disk capacity	Performance: High Read and write performance, high random write performance Security: No redundancy, no hot spare, no fault tolerance, low security	Quick read and write without fault, requires no high security, such as graphics workstation.
RAID 1	Mirrored storage. The principle is to write the same data to each disk in the array, to maximize the availability and repair of user data. The downside is high storage costs.	Number of hard disks: two or 2*n Capacity: 50% of total disk capacity	Performance: Low read/write performance, low random write performance Security: Redundancy with replication, hot spares, fault tolerance, high security	Random data writing requires high security, such as server, database storage domain.
RAID 5	Distribution of odd and even bit bands. is a storage solution that balances performance, data security, and storage costs, and is understood as a compromise between RAID 0 and RAID 1. The principle is to store data and corresponding parity information on each disk that makes up RAID5, and parity information and corresponding data are stored on separate disks. When a RAID5 disk data is corrupted, the corrupted data is recovered using the remaining data and the corresponding parity information. Compared to RAID 0, there is just one more parity information. Multiple data can correspond to one parity information.	Number of hard disks: three or more Capacity: (n-1)/n Total disk Capacity (n is the number of disks)	Performance: Low random and continuous write performance, high read performance Security: The use of parity for redundancy, fault tolerance, high security	Random data transmission requires high security, such as finance, database, storage and so on.
RAID 10	Mirrored array strip. Balance storage performance and data security with RAID 1-like data security, with raid 0-approximate storage performance. The downside is high storage costs.	Number of hard disks: four or 4*n Capacity: 50% of total disk capacity	Performance: Moderate read and write performance Security: Use replication for redundancy, fault tolerance, high security	It is suitable for requiring large amount of data access and high security, such as banking, finance and other fields.
The difference between RAID 10 and RAID 01: RAID 10 and RAID 01 are different combinations of two logical ways. RAID 10 is the first mirror after the tape, that is, the hard drive portrait of the first mirror, and then the horizontal strip. In this case, the raid group will not crash as long as several hard drives in the same mirror group are not broken. That is, the hard drive of the same mirror group cannot be broken at the same time. RAID 01 is a first-band mirror image, that is, the hard drive horizontal strip, and then portrait mirroring. In this case, the entire RAID group will not crash as long as the hard drive is not broken on both strips. Whether or not the two hard drive in which the media is damaged is a mirrored disk. That is, the hard drives of different stripe groups cannot be broken at the same time. RAID 10 and RAID 01 are essentially the same in performance, but raid 01 is more likely to fail than raid 10. So in general, RAID 10 is selected.

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