Brief description of the difference between RAID0, RAID1 and RAID5

RAID (Redundant array of independent Disks, redundant array of independent disks ) provides higher speed and security for normal side disks. All servers will choose to create raid when they are installed. There are two ways to create a raid: Soft RAID (implemented via operating system software) and hard raid (using hardware array cards)

1.raid-0:strinping (stripe mode), requires at least two fast disks, the size of the RAID partition is preferably the same (can give full play to the concurrency advantage), the data is distributed on different disks, can be implemented concurrently when reading and writing, all relative to their best read and write performance; However, there is no fault-tolerant function, the damage of any one disk will destroy all data; disk utilization is 100%;

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/7D/56/wKiom1bmV_GAFhUiAABUfD0ZhmA349.png "title=" 1.png " alt= "Wkiom1bmv_gafhuiaabufd0zhma349.png"/>

2.raid-1:mirroring (mirrored volume), requires at least two hard disks, the raid size is equal to the minimum capacity of two raid partitions (preferably dividing the partition size), the data is redundant, when the storage is written to two hard disks, data backup, disk utilization is 50%, That is, 2 fast 100G hard drive composition RAID1 can only provide 100G of free space.

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/7D/56/wKiom1bmWO-xth2iAABA5jUUcWU553.png "title=" 2.png " alt= "Wkiom1bmwo-xth2iaaba5juucwu553.png"/>

3.raid-5: Requires three or more hard drives, can provide a hot spare to achieve fault recovery; only one piece is damaged, no problem. However, if both disks are damaged at the same time, the data is corrupted. Utilization:(n-1)/n 2/3

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/7D/55/wKioL1bmWoWi9yDdAABTaGlcgO8428.png "title=" 3.png " alt= "Wkiol1bmwowi9yddaabtaglcgo8428.png"/>

is a relatively simple XOR operation (the same as 0, the difference is 1)

A value B value XOR result

0 0 0

1 0 1

0 1 1

1 1 0

==============================================

The A and B values here represent two bits, where A and B are the same, the XOR result is 0,a and B are different, the XOR result is 1, and knowing the XOR result and any of the values in A and B, you can send out another value

Note: Hot spare or Standby driver: In order to enhance fault-tolerant functionality and to enable the system to rapidly rebuild data in the event of a disk failure to maintain system performance, a typical disk array can use the hot backup function

Chunk (FAST): the size of each data segment when the RAID data is stored. 4K 64K

Brief description of the difference between RAID0, RAID1 and RAID5