RAID0 RAID1 RAID5 RAID10 Difference

RAID (Redundant array of independent disk independent Redundant array) technology was proposed by the University of California, Berkeley, in 1987, initially to combine small, inexpensive disks in place of large expensive disks, while hoping that the disk will fail without damaging access to the data Development of a certain level of data protection technology. RAID is a redundant array of inexpensive disks that appear as a separate, large storage device under the operating system. RAID can give full play to the advantages of multiple hard drives, can increase the speed of the hard disk, increase capacity, provide fault-tolerant work to ensure data security, easy to manage the advantages of any one hard disk problems can continue to operate, not affected by the damage to the hard drive.

RAID is an abbreviation for the redundant Array of indepent Disks (redundant array of independent disks), the four most commonly used raid is RAID 0, RAID 1, RAID 5, RAID 10, and the following illustrates the features and differences of these four types of RAID graphically.

In a later illustration, the following identification is used: A,b,c,d,e and F-represents a block of data p1,p2,p3-represents a block of parity information

RAID 0

RAID 0 Features: A minimum of two disk data stripe distribution without redundancy, the best performance (do not store the image, check information) can not be applied to the high data security requirements of the occasion

RAID 1

The following features are RAID 1: a minimum of 2 disks is required to provide data block redundancy performance.

RAID 5

RAID 5 Features: Minimum of 3 disks data stripe form distribution with parity as redundancy for multi-read and less-write scenarios, the best compromise between performance and data redundancy

RAID 10

RAID 10 (also known as RAID 1+0) features: A minimum of 4 disks by RAID 0 is divided into two groups, respectively, the two groups by RAID 1 mode of mirroring the redundancy (provide mirrored storage) and performance (data stripe distribution) in practical applications are more commonly used

RAID 0 is the data stripping (striped technology). The data of the entire logical disk is distributed across multiple physical disks by a stripe (stripped), which can be read/written in parallel, providing the fastest speed, but without the redundancy capability. Requires a minimum of two disks. With raid 0, we can obtain a larger capacity of a single logical disk and gain higher access speeds by simultaneously reading multiple disks. RAID 0 The first consideration is the speed and capacity of the disk, ignoring the security, as long as one of the disks is a problem, the entire array of data will be out of warranty.

Q: RAID0 at least a few pieces of disk.
A: RAID0 requires a minimum of two hard drives to achieve.

RAID 1
RAID 1, also known as mirroring mode, is the redundancy of the data. During the entire mirroring process, only half of the disk capacity is valid (the other half of the disk capacity is used to hold the same data). Compared to RAID 0, RAID 1 first considers security, which is half the capacity and the same speed.

Q: RAID1 at least a few pieces of disk.
A: RAID1 requires a minimum of two hard drives to achieve.

RAID 0+1 (RAID 10)
In order to be both fast and secure, RAID 10 (or RAID 0+1) appears, and RAID 10 can simply be interpreted as a RAID 0 array composed of multiple disks for mirroring.

Q: raid0+1 at least a few hard drives can be implemented.
A: raid0+1 requires at least 4 disks.

RAID 3 and RAID 5
Both RAID 3 and RAID 5 are checksum modes. RAID 3 works by storing the checksum data with a disk. Because any data changes to modify the corresponding data check information, the disk that holds the data has several and parallel work, and the disk that holds the check data is only one, which brings the bottleneck of verifying data storage. RAID 5 works by dividing the data generated by each disk into chunks that are stored in the respective disks that make up the array, thus easing the bottleneck that occurs when the checksum data is stored, but the cost of splitting the data and controlling the storage is at a speed.

Q: How many hard drives does RAID5 need? Why is the volume of a disk lost?
Answer: at least 3 bucks.
RAID5 stores the data and the corresponding parity information on each disk that makes up the RAID5, and the parity information and the corresponding data are stored on separate disks, where the full data is stored on any N-1 block disk, meaning that there is space equivalent to a disk capacity for storing parity information. Therefore, when a disk in RAID5 is damaged, the data integrity is not affected, thus ensuring data security. When the damaged disk is replaced, the raid also automatically rebuilds the data on the disk with the remaining parity information to maintain the RAID5 's high reliability.

Reprint: http://www.cnblogs.com/Bob-FD/p/3409221.html