Graphic RAID 0, RAID 1, RAID 5, RAID 10

Graphic RAID 0, RAID 1, RAID 5, RAID 10

RAID (Redundant Array of Independent Disk Independent Redundant Disk Array) technology was proposed by the University of California at Berkeley in 1987, initially to combine small cheap disks to replace large expensive disks, at the same time, we hope that when the disk fails, data access will not be damaged and a certain level of data protection technology will be developed. RAID is a Redundant Array composed of multiple low-cost disks. It appears as an independent large storage device in the operating system. RAID can fully leverage the advantages of multiple hard disks, increase the hard disk speed, increase the capacity, and provide Fault Tolerance functions to ensure data security and ease of management, you can continue to work in the case of any hard disk failure, without being affected by the damage to the hard disk.

RAID is the abbreviation of Redundant Array of Indepent Disks (Redundant Array of Independent Disks). The four most commonly used RAID types are RAID 0, RAID 1, RAID 5, and RAID 10, the features and differences of the four RAID types are illustrated below.

In the following illustration, the following identifier is used:

• A, B, C, D, E, and F-represent data blocks.
• P1, p2, p3-indicates the parity information block

 

RAID 0

RAID 0 features:

• At least two disks are required.
• Distribution of data entries
• No redundancy and optimal performance (no image or verification information is stored)
• It cannot be used in scenarios with high data security requirements.

 

RAID 1

The features of RAID 1 are as follows:

• At least two disks are required
• Data Block Redundancy
• Good performance

 

RAID 5

RAID 5 features:

• At least 3 Disks
• Data Band distribution
• Use parity for redundancy
• It is suitable for scenarios with multiple reads and writes, and is the best compromise between performance and data redundancy.

 

RAID 10

 

RAID 10 (also known as RAID 1 + 0) features:

• At least 4 disks are required
• Divide the two groups into two groups by RAID 0, and then mirror the two groups by RAID 1.
• Redundancy (image storage) and performance (data strip distribution)
• Frequently Used in practical applications

RAID 0 is Data Stripping (Data sharding technology ). The data on the entire Logical Disk is distributed across multiple physical disks, and can be read/written in parallel to provide the fastest speed, but there is no redundancy capability. At least two disks are required. We can use RAID 0 to obtain a larger capacity for a single logical disk, and get a higher access speed by simultaneously reading multiple disks. RAID 0 first considers the disk speed and capacity, ignoring the security. As long as one of the Disks has a problem, the data in the entire array will not be guaranteed.

Q: How many disks does RAID0 have?
A: RAID 0 requires at least two hard disks.

RAID 1
RAID 1, also known as the image method, is the data redundancy. In the entire image process, only half of the disk capacity is valid (the other half is used to store the same data ). Compared with RAID 0, RAID 1 first considers security, halving the capacity, and changing the speed.

Q: How many disks does RAID1 have?
A: Raid 1 requires at least two hard disks.

RAID 0 + 1 (RAID 10)
To achieve high speed and security, RAID 10 (or RAID 0 + 1) can be simply split into a RAID 0 array consisting of multiple disks for mirroring.

Q: How many hard disks can RAID0 + 1 be implemented?
A: RAID0 + 1 requires at least four disks.

RAID 3 and RAID 5
Both RAID 3 and RAID 5 are verified. RAID 3 uses a disk to store verification data. The corresponding data verification information must be modified for any data changes. The disk that stores the data has several parallel operations, and the disk that stores the verification data has only one disk, this leads to a bottleneck in verifying data storage. RAID 5 is used to cut the data validation generated by each disk into blocks and store them in each disk that forms an array, this relieves the bottleneck during data storage verification. However, data splitting and storage control are all subject to a high speed.

Q: How many hard disks does RAID5 need? Why is the capacity of a disk lost?
A: At least three.
RAID5 stores the data and the corresponding parity information on each disk that makes up RAID5, And the parity information and the corresponding data are stored on different disks respectively, any of these N-1 block disks Store complete data, that is, there is space equivalent to a disk capacity for storing parity information. Therefore, when a disk in RAID 5 is damaged, data integrity is not affected, thus ensuring data security. After a damaged disk is replaced, RAID will automatically use the remaining parity information to reconstruct the data on the disk to maintain the high reliability of RAID 5.

How to build a RAID 10 array on Linux

Debian soft RAID Installation notes-use mdadm to install RAID1

Common RAID technology introduction and demo (Multi-chart)

The most common disk array in Linux-RAID 5

RAID0 + 1 and RAID5 Performance Test Results

Getting started with Linux: disk array (RAID)

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