What is RAID technology for servers?

The server is generally powered on and press the Ctrl+R key combination to enter the RAID array configuration interface, and there is an explanation of Hungry Oak.

2.Lenovo server lead diviner in the thinksystemlogo when press f1 to enter the lxpm interface,There is raidsetup。....

Server, boot some press Ctrl+A, Ctrl+C, Ctrl+H, etc., if the system is installed with relevant array management software, you can directly see the array information, such as serveraidmanager, etc.

Disk array servers.

RAID 0: Merge multiple smaller disks into one large disk, without redundancy, parallel IO, and the fastest. RAID 0 is also known as a bandset.

It is the juxtaposition of multiple disks into one large hard disk. When storing data, it segments the data by the number of disks, and then writes the data to those disks at the same time. So, out of all the levels, RAID 0 is the fastest.

However, RAID 0 does not have redundancy, and if one disk is (physically) damaged, all data is unusable.

RAID 1: Two identical disk systems mirror each other, the speed is not improved, but a single disk error is allowed, and the reliability is the best. RAID 1 is the mirror.

The principle is to store data on the main hard disk and write the same data on the mirror hard disk at the same time. When the primary hard drive is (physically) damaged, the mirrored hard drive takes the place of the primary hard drive. RAID 1 data security is the best of all RAID levels because there is a mirrored hard drive for data backup.

However, its disk utilization is only 50%, which is the lowest level of disk utilization of any RAID.

RAID Level 3 RAID 3 stores data differently from RAID 0 and RAID 1. RAID 3 stores the parity bit of data on one hard disk, and the data is stored in segments on the rest of the hard disk. It stores numbers in parallel like RAID 0, but not as fast as RAID 0.

If the data disk is (physically) damaged, just replace the bad hard disk with RAID

The control system will reconstruct the data on the bad disk according to the data of the check disk in the new disk. However, if the calibration disk is (physically) damaged, all data will be unusable. Although the use of a separate check disk to protect data is not as secure as the mirror, the utilization rate of the hard disk has been greatly improved, which is n-1.

RAID 5: Writes data to disks in the array, parity data is stored on individual disks in the array, and punching allows for errors on individual disks. RAID 5 also uses the check digit of the data to ensure the security of the data, but it does not store the check digit of the data in a separate hard disk, but stores the check digit of the data segment on each hard disk.

In this way, any hard drive that is damaged can be reconstructed based on the check digits on the other hard drives. The utilization rate of the hard disk is n-1. If the funds are sufficient, it is recommended to buy three hard disk groups raid1, the security of the data is the best, and there will be no hard disk breakage, and the data will not be used.

Redundant arrays of independent disks (RAID), yes"A redundant array of independent disks"meaning.

The disk array is composed of many cheaper disks combined into a huge capacity of the Hail Sun faction disk group, using individual disks to provide data to produce a bonus effect to improve the performance of the entire disk system. Using this technology, the data is sliced into many segments and stored on separate hard drives.

Disk arrays can also use the concept of parity check, which can still read data in the event of a failure of any hard disk in the array, and when the data is reconstructed, the data will be calculated and re-placed into a new hard drive.

The disk array is connected to the host directly outside the host or over the network as a stand-alone system. A disk array has multiple ports that can be connected by different hosts or different ports. A host connects different ports to the array to increase transfer speeds.

Just like the integrated cache on a single disk for PCs at the time, there is a certain amount of buffer memory inside the disk array to speed up the interaction with the host. The host interacts with the disk array's cache, and the cache interacts with the specific disk data.

In the application, there are some commonly used data that need to be read frequently, and the disk array finds out the data that is often read by the Kaizhi according to the internal algorithm, and stores it in the cache to speed up the host to read these data sources, and for the data that is not in other caches, the host wants to read it, and the array directly reads and transmits it to the host from the disk. For data written by the host, it is only written to the cache, and the host can complete the write operation immediately. It is then slowly written to disk from the cache.