Linux Learning Note--raid

Raid

Redundant array of independent hard disks (RAID, redundant array of independent Disks), formerly redundant Array of inexpensive disks (redundant array of inexpensive Disks), referred to as disk arrays.

Divided into raid-0,raid-1,raid-2,raid-3,raid-4,raid-5,raid-6,raid-7,raid-10,raid-50,raid-60. Where raid-0,raid-1,raid-2,raid-3,raid-4,raid-5,raid-6 is the standard raid,raid-7,raid-10,raid-50,raid-60 for hybrid RAID.

Standard raid

RAID 0 650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/72/53/wKiom1Xgbm6x_4RgAABTzcXpLOY247.jpg "title=" Qq20150828222058.png "width=" 98 "height=" "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:98px;height:150px;float: right; "alt=" wkiom1xgbm6x_4rgaabtzcxploy247.jpg "/>

RAID 0 is a large-capacity disk that has more than two disks connected in parallel. When the data is stored, the data is segmented and stored
In these disks, the parallel processing of data reading and writing can greatly improve the I/O capability of the disk. However, RAID 0 does not have redundancy and fault tolerance, and if one disk is damaged, the data will be lost.

Free space: n*min (S1,s2,...)

RAID 1

RAID 1 Mirrors more than two sets of n disks with one another. Store data on multiple disks, 650) this.width=650; "Src=" http://s3.51cto.com/wyfs02/M01/72/53/ Wkiom1xgbr6tgpf6aabnyndtvk4583.jpg "title=" Qq20150828222238.png "width=" "height=" "border=" 0 "hspace=" 0 " Vspace= "0" style= "Color:rgb (0,0,238); width:99px;height:150px;float:right;" Alt= " Wkiom1xgbr6tgpf6aabnyndtvk4583.jpg "/> As long as a disk is normal to maintain operation, the highest reliability. Disk reads are improved, but write power drops slightly, and disk utilization is greatly reduced because multiple disks store the same data.

Free space: 1*min (S1,s2,...)

RAID 2

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/72/53/wKiom1XgbvKzljlIAACmyBvsxkA123.jpg "title=" Qq20150828222027.png "style=" float:right; "alt=" wkiom1xgbvkzljliaacmybvsxka123.jpg "/>

This is a modified version of RAID 0, where the data is encoded in Hamming code (Hamming code) and partitioned into separate bits, and the data is written to the hard disk separately. Because the error correction code (ecc,error Correction code) is added to the data, the overall capacity of the data is larger than the original data, and the RAID2 can operate at least three disk drives.

RAID 3

Using the bit-interleaving (Data interleaved storage) technology, it needs to be encoded and then split the data bit after the hard disk, and the same bit after the inspection of a separate hard disk, but because the data within the bits scattered on different hard disks, So even if you want to read a small piece of data, all the hard drives may be required to work, so this specification is more suitable for reading large amounts of data.

RAID 4

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M02/72/53/wKiom1Xgchqi6QzNAABvi31Osjc180.jpg "style=" float: right; "title=" Qq20150828223647.png "alt=" Wkiom1xgchqi6qznaabvi31osjc180.jpg "/>

With more than three disks, one of the disks as a check disk, the other disks to segment the data storage, when a piece of disk corruption is, because the existence of the check disk, so data is not lost.

RAID 5

RAID 5 is a storage solution that combines storage performance, data security, and storage costs. It uses disk 650) this.width=650; "Src=" http://s3.51cto.com/wyfs02/M01/72/4F/wKioL1XgdYWhVrnoAABy4Xg6cSc669.jpg " Title= "Qq20150828224111.png" style= "float:right;" alt= "Wkiol1xgdywhvrnoaaby4xg6csc669.jpg"/>Striping (hard disk partitioning) technology. RAID 5 requires at least three hard drives, RAID 5 does not back up the stored data, but instead stores the data and the corresponding parity information on each disk that makes up the RAID5, and the parity information and the corresponding data are stored on separate disks. When one of RAID5 's disk data is damaged, it can recover the corrupted data using the remaining data and the corresponding parity information. RAID 5 provides data security for the system, but with a lower level of protection than mirroring and higher disk space utilization than mirroring. Read and write performance is relatively elevated.

Free space: (N-1) *min (s1,s2,...)

RAID 6

RAID 6 adds a second independent parity information block compared to RAID 5. Two independent parity systems using different

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/72/4F/wKioL1Xgdifh4PEWAACTzzOPYU0810.jpg "title=" Qq20150828224502.png "style=" float:right; "alt=" wkiol1xgdifh4pewaactzzopyu0810.jpg "/> Algorithm, the data reliability is very high, Any two disks that fail at the same time do not affect data integrity.

Free space: (N-2) *min (s1,s2,...)

Hybrid raid

RAID 7

RAID 7 is not a publicly available RAID standard, but rather a patented hardware product name for storage Computer Corporation.

RAID 10/01

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/72/50/wKioL1XgecnjATlVAAD-BuFE_KY063.jpg "title=" Qq20150828225102.png "style=" float:right;width:179px;height:350px; "width=" 179 "height=" "border=" 0 "hspace=" 0 " Vspace= "0" alt= "wkiol1xgecnjatlvaad-bufe_ky063.jpg"/>

RAID 10 is the first mirror-and-partition data, then divides all the drives into two groups, considered the lowest combination of RAID 0, and then

Each of the two groups is considered to be RAID 1 operations.

Raid 01 is the reverse of a RAID 10 program, which partitions and then mirrors the data into two groups of hard disks. It divides all the hard drives into two groups, becoming the lowest combination of RAID 1, while the two groups of hard disks are considered RAID 0 respectively.

RAID 10 when one of the hard drives is damaged, the other disks work, while RAID 01 has a disk that is damaged, and the raid 0 disks in the same group will cease to function. When multiple disks in a RAID 10 group are damaged, the data is not lost as long as one of the disks in each group is functioning correctly, and the data is lost when multiple disks in the RAID 11 denier group are damaged.

RAID 50

RAID 5 is a combination of RAID 0, first RAID 5, and then raid 0.

RAID 60

Combination of RAID 6 and RAID 0: RAID 6 first, then RAID 0.

Linux Learning Note--raid