Shulou(Shulou.com)05/31 Report--

In this issue, the editor will bring you the knowledge about the principles of disk array RAID and array cards. The article is rich in content and analyzes and describes for you from a professional point of view. I hope you can get something after reading this article.

Let's take a look at disk arrays today.

I. introduction of RAID disk array

■ RAID is the abbreviation of Redundant Array of Independent Disks in English and independent redundant disk array in Chinese.

■ RAID combines multiple independent physical hard drives in different ways to form a hard disk group (logical hard disk), thus providing higher storage performance and data backup technology than a single hard disk.

The different ways in which ■ forms a disk array are called RAID levels (RAID Levels). The commonly used RAID levels are as follows: RAIDO, RAID1,RAID5,RAID6, RAID1+0, etc.

1. Spanned volumes (LVM volumes)

Features: scalability

Composition conditions: can be appended from disks of different sizes

Capacity: total capacity of multiple disks

two。 Striped volumes (stripes): RAID 0

Features: highly written

Disadvantages: unreliable

Composition condition: composed of disks of the same size

Capacity: total capacity of multiple disks

3. Mirrored volumes: RAID 1

Features: high reliability, can lose a disk

Disadvantages: lack of scalability

Composition condition: composed of disks of the same size

Capacity: half of the total capacity of multiple disks

4.RAID 5 Volume

Features: high reading, general writing, high reliability, allowing damage to a disk.

Composition: at least 3 disks of the same size

Capacity: (nmur1) / nTotal disk capacity

5.RAID 6

Features: compared with RAID5, RAID 6 adds a second independent parity block

Advantages: even if two disks fail at the same time, it will not affect the use of data.

Disadvantages: greater "write loss" than RAID 5, so write performance is poor

Composition: at least 4 disks of the same size

Capacity: (Nmur2) / N capacity

6.RAID 10 (RAID1+0)

Features: a combination of striped volume (RAID 0) and mirrored volume (RAID 1), good performance, high reliability, data

Composition condition: at least 4 disks are written at the same time, and N-block disks are read at the same time, one disk in the same base group is allowed to be damaged, but the disks in the same base group are not allowed to be damaged at the same time.

II. Introduction of array cards

1. The board used to implement the RAID function is usually composed of a series of zero components such as the Imax O processor, the hard disk controller, the hard disk connector and the cache.

two。 Different raid cards support different RAID functions, such as RAID 0, RAID 1, RAID 5, RAID 10, etc.

3. Interface types of raid card: IDE interface, SCSI interface and SAS interface.

The above is the principle knowledge of disk array RAID and array card shared by Xiaobian. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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