Frequently used raid easy to read and remember

RAID is a "cheap duplicate disk array", meaning that multiple drives using a commercial product can be used for high availability or performance purposes. There are also different combinations depending on the number of drives used, the purpose, and the number of hard drives that are fault tolerant.

1.RAID 0

A principle:RAID 0 is the total number of all N multi-drive, when pressed into the data, the data will be split into N parts, pressed into different hard disks.

B participating HDD: At least two, capacity is (minimum capacity HDD *n), four 1T hdd, compose RAID 0, capacity is 4T.

C Security:RAID 0 does not have any safe mode, so when any one hard drive fails, the entire data is incomplete and unreadable.

D Performance: All data read and write are n accompany speed, can read and write n multiple hard drives concurrently.

E Use cases: speed is required, but data security is not required.

2.RAID 1

A principle:RAID 1 is the way to use mirroring for 2 hard drives. When the data is pressed in, the data is mirrored and then pressed into two hard drives.

B participating HDD: Two required, capacity (minimum capacity HDD). 2 x 1T hard disks, composed of RAID 1and 1T capacity .

C Security:RAID 1 with mirroring mode, so any one hard disk failure, the other corresponding hard disk has full data, you can continue to use, allowing 1 hard drives to be broken .

D Performance:RAID 1 is only twice times faster when it is readable. Because you can read the same data from different hard disks, there is no speed added when you can write.

E Use occasions: The most complete security combination, always have two full data of the hard disk.

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3.RAID 10

A principle:raid is a combination of RAID 1 and RAID 0 , which can be said to combine two RAID1 raid into RAID 0.

B participate in HDD: Minimum 4 , Capacity (minimum capacity)*n/2,4 1T hdd, compose RAID, capacity 2T .

C Security:RAID has a mirror, so when any one failure, the other corresponding hard disk has a complete data, you can continue to use.

D Performance : RAID 1 can be considered as a combination of the RA hard drive ID 0, so readable is N times, can be written n/2 times.

E Use occasions: concurrency requires high performance and security.

4.RAID 5

A principle: Using multiple hard disks, and using XOR to generate checksum data, officer data scattered across multiple.

B participating HDD : minimum 3 , Capacity (minimum capacity HDD)* (n-1), 3 1T hard disk , RAID5, 2T capacity .

C Security:RAID 5 has a checksum mode, so when any one hard drive is damaged, the remaining hard drive can get lost data through XOR calculation, can continue to use, but speed back down, because the need to operate, allow bad one hard drive.

D Performance:RAID 5 needs to be verified, so it depends on the chip computing power of the raid card.

E Use occasions: balance of space, performance and safety,

This article is from the "shallow if the words" blog, please be sure to keep this source http://allmrys.blog.51cto.com/1612968/1783268

Frequently used raid easy to read and remember