RAID disk array

Catalog

RAID Disk display

experiment

RAID 5

 RAID 0

RAID 1

RAID 1 0 

---

RAID Disk display

yes Redundant Array ofIndependent Disks Abbreviation , Chinese abbreviation is Independent redundant disk array

frequently-used RAID Level
RAID0,RAID1,RAID5,RAID6,RAID1+0 etc.

	Disk utilization	Whether the recovery can be verified	Security	Write performance
RAID 0	N	nothing	nothing （ Only fast ）	On a single disk N times
RAID 1	N/2	nothing	Allow a device failure	You need to write two storage devices , Prepare for each other
RAID 5	(N-1)/N	Yes	Allow a device failure	Need to calculate and verify
RAID 6	(N-2)/N	nothing	Two equipment failures are allowed	Double write calculation verification is required
RAID 1 0	N/2	nothing	Allow two base groups to break one each	N/2 The disk is written simultaneously

RAID 0

RAID 0 Divide data continuously in bits or bytes , Read in parallel / Write on multiple disks , Therefore, it has high data transmission rate , But it has no data redundancy
RAID 0 Just to improve the performance , There is no guarantee for the reliability of the data , And a disk failure will affect all data
RAID0 It can't be used in the situation with high data security requirements

RAID 0 Characteristics

You need at least two disks
Distributed data strip
There is no redundant , Best performance （ Do not store images 、 Check information ）
It can't be used in the situation of high data security

RAID 1

Realize data redundancy through disk data mirroring , Generate backup data on a pair of independent disks
When raw data is busy , Data can be read directly from the mirror copy , therefore RAID 1 Can improve read performance
RAID 1 It's the highest cost per unit in a disk array . But it provides high data security and availability . When a disk fails , The system can automatically switch to read and write on the mirror disk , And there's no need to reorganize failed data .

RAID 1 Characteristics

You need at least two disks
Provide data redundancy （ Provide backup ）
Good performance

RAID 5

N(N≥3) The disks form an array , A data generation N-1 A strip , There is also a verification data , common N The data is in N Cycle balanced storage on the block disk
N Read and write at the same time , High reading performance , But because of the problem of checking mechanism , Write performance is relatively low
（N-1）/N Disk utilization
High reliability , Allow one disk to break , It doesn't affect all the data

RAID 5 Characteristics

least 3 Block disk
The data is striped
Redundancy with parity
Suitable for reading more and writing less , It's the best compromise between performance and data redundancy
 

RAID 6

N（N≥4） The disks form an array ,（N-2）/N Disk utilization

And RAID 5 comparison ,RAID 6 A second independent parity information block is added

Two independent parity systems use different algorithms , Even if two disks fail at the same time, data usage will not be affected

be relative to RAID 5 There are bigger ones “ Write loss ”, Therefore, the write performance is poor

RAID 1+0( First make a mirror image , And then make a strip )

N ( even numbers ,N>=4). After two disks are mirrored , Then combine it into a RAID 0
N/2 Disk utilization
N/2 All disks are written simultaneously ,N All disks are read at the same time
High performance , High reliability

RAID 1+0 Characteristics

least 4 Block disk
According to the first RAID 0 Divide into two groups , And then press RAID 1 Mode image
Take care of redundancy （ Provide mirrored storage ） And performance （ The data is striped ）
It is commonly used in practical application
 

experiment

RAID 5

1. First fdisk -l Check the added disks

2. Then divide the four disks into main areas （ The operation of the four disks is the same ）

 3. After dividing fdisk Check it out.

 4. install mdadm（ Already installed can also yum to update ）

5. Create and view raid 5

6. View disk details

7. Create a new directory , Mount after formatting

8. Try to make a disk fail , See whether the empty disk can replace the faulty disk

 RAID 0

Divide the main area and install mdadm Reference resources raid5

RAID 1

Divide the main area and install mdadm Reference resources raid5

RAID 1 0 

Divide the main area and install mdadm Reference resources raid5