Recently, there is a problem of data loss on the hard disk that has been plaguing everyone. Today we talk about the principle of RAID technology for everyone to understand storage-related technologies.
1. What is Raid
Redundant Array of Inexpensive Disks (RAID) is called a redundant array of inexpensive disks. The basic principle of RAID is to combine multiple inexpensive small disks into a single disk group to achieve performance or exceed a large, expensive disk.
Currently, RAID technology is roughly divided into two types: hardware-based RAID technology and software-based RAID technology. The RAID function can be implemented under Linux with its own software, which can greatly enhance the IO performance and reliability of the disk by eliminating the need to purchase expensive hardware RAID controllers and accessories. Because it is a RAID function implemented by software, it is flexible in configuration and convenient in management. Using software RAID at the same time, it is also possible to combine several physical disks into one larger virtual device for performance improvement and data redundancy. Of course, hardware-based RAID solutions outperform software-based RAID technology in terms of performance and service performance, in terms of the ability to detect and fix multiple errors, automatic disk detection, and array reconstruction.
2. RAID level introduction
Raid levels commonly used in production scenarios are: Raid 0, Raid 1, Raid 5, Raid 10 (Raid 0 + Raid 1)
RAID 0:
Also known as striped, that is, contiguous data is spread across multiple disks for access, as shown. When the system has a data request, it can be executed in parallel by multiple disks, and each disk executes its own part of the data request. This parallel operation on the data can make full use of the bandwidth of the bus and significantly improve the overall access performance of the disk. Because reads and writes are done in parallel on the device, read and write performance will increase, which is often the main reason for running RAID 0. However, RAID 0 has no data redundancy, and if the drive fails, no data can be recovered.
RAID 1:
RAID 1 is also known as mirroring, a fully redundant mode, as shown. RAID 1 can be used for two or 2xN disks and uses zero or more spare disks, which are written to the mirror disk each time data is written. This array is highly reliable, but its effective capacity is reduced to half of the total capacity, and the size of these disks should be equal, otherwise the total capacity will only have the smallest disk size.
RAID 5:
RAID5 stores the data and the corresponding parity information on each disk that constitutes RAID5, and the parity information and the corresponding data are stored on different disks, and any N-1 disks are stored on the disk. Data, that is, a space equivalent to a disk capacity for storing parity information. Therefore, when a disk of RAID 5 is damaged, the integrity of the data is not affected, thereby ensuring data security. When the damaged disk is replaced, RAID will automatically use the remaining parity information to reconstruct the data on this disk to maintain the high reliability of RAID5.
RAID 5 can be understood as a compromise between RAID 0 and RAID 1. RAID 5 can provide data security for the system, but the degree of protection is lower than the mirror and the disk space utilization is higher than the mirror. RAID 5 has a data read speed similar to that of RAID 0, except that because of the extra parity information, the speed of writing data is slightly slower than writing to a hard disk separately.
RAID 10:
Raid 10 is a combination of Raid 1 and Raid0. It implements stripe set mirroring using parity, so it inherits Raid0's fast and Raid1 security. We know that RAID 1 is a redundant backup array here, while RAID 0 is responsible for the read and write array of data. In fact, the picture on the right is just a RAID 10 method. In more cases, two paths are separated from the main path. The Striping operation is performed, that is, the data is divided, and each of the separated channels is divided into two paths to perform the Mirroring operation. That is, mirroring each other.
With the development of RAID disk array technology, storage performance and security are well protected. Data is not lost easily. Even if the data is really lost, there are certain data recovery technologies that can be recovered, depending on whether you really want to keep the data.
Washing Machine Motor,Spin Motor Of Aluminium Wire,Washing Machine Motor Shaft,Automatic Washing Machine Spin Motor
WUJIANG JINLONG ELECTRIC APPLIANCE CO., LTD , https://www.jinlongmotor.com