Server hardware and RAID configuration practice

Catalog

One ,RAID Disk array Introduction

RAID 0（ Striped storage ）

 RAID 1（ Mirrored storage ）

RAID 5

RAID 6

RAID 1+0

each RAID Zone between levels

  Two , Disk array practice

RAID 0

 RAID 1

 RAID 5

 raid 10

  summary

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One ,RAID Disk array Introduction

yes Redundant Array of lndependent Disks Abbreviation , Chinese abbreviation is independent redundant disk array .

Combine several independent physical hard disks in different ways to form a silver disk group （ Logical hard disk , So as to provide higher storage performance than a single hard disk and provide data backup technology

The different ways to make up a disk array are called RAID Level （RAID Levels）

frequently-used RAID Level

RAID0   RAID1  RAID5 RAID6 RAID1+0 etc.

RAID 0（ Striped storage ）

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 simply improve performance , There is no guarantee for improving the reliability of data , And the failure of one of the disks will affect all the data

RAID 0 It can't be used in the situation with high data security requirements

N The fast hard disks are combined in parallel into a new logical disk

explain ：RAID 0 It is to connect more than two hard disks in parallel , towards RAID 0 When storing data , It will be distributed and stored in all disks under it . Reading and writing are done from multiple disks , So reading and writing speed is very fast , But there is no redundancy , One hard disk is broken , Whole RAID 0 Your data will be lost . 

 RAID 1（ Mirrored storage ）

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

N An even number of fast hard disks form an image ,N/2 Capacity

explain ：RAID 1 Must be a paired disk combination , At least 2 A disk , A disk is the most normal use , Another disk as a backup , When the disk in normal use is busy or damaged , You can switch to the backup disk for reading and writing . Data written to RAID 1 It takes a long time , Because you need to write data to two disks , The reading speed does not change , But it can improve performance , Effective reading （ One is broken , You can go to another one to read ）.
 

RAID 5

N（N>=3） Fast disks form an array , A data generation n-1 A strip , As well as 1 Validation data , common N The sub data is N Cycle on the disk

N Read and write at the same time , High reading performance , Due to the problem of effective mechanism , Write performance is relatively low

（N-1）/N Disk utilization , High reliability , Allow blocks 1 Block plate , Does not affect all data

explain ：RAID 5 Minimum need 3 It's made up of two disks , Two disks are the storage of data , A disk is the verification data , Data reading and writing of data storage disk RAID 1（ Distributed storage ） It's the same , But there is a verification mechanism , So the writing speed is relatively RAID 0 A little worse , The reading speed is very high . Any disk data is lost or damaged , Will not lead to the loss of the entire data , Because the disk with verification mechanism will calculate the damaged disk content data through other undamaged disks .

RAID 6

N （N>=4）  The plates form a whole column ,（N-2）/N Disk utilization

And RAID 5 comparison ,RAID 6 Added a second independent surprise   Even check information is fast

Two independent wonders   Even systems use different algorithms , Even if the two disks fail at the same time, the use of image data will not

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

RAID 1+0

N ( even numbers ,N>=4) After two mirrored disks , In combination into one RAID 0

N /2 Disk utilization

N/2 The fast disk is written at the same time ,N The disks are read, written and accessed at the same time

High performance , High reliability

  explain ：RAID 1+0 array , First two hard disks RAID 1, Then two more RAID 1 Make it RAID 0, It is equivalent to having backup function and improving reading speed . Write to 4 Block disk for writing , Writing is slow , Read read from multiple disks , It's very efficient . And there is a backup mechanism .

each RAID Zone between levels
 

RAID Level	Hard disk space	Disk utilization	The ability to protect	Write performance
RAID 0	N	N	nothing	The hard disk N times
RAID 1	N( even numbers )	N/2	nothing	Write two pairs of storage devices , Prepare for each other
RAID 5	N>3	(N-1)N	Yes	Need to write calculation validity
RAID 6	N>4	(N-2)N	Yes	Double counting test is required
RAID 10	N>=（ even numbers ）	N/2	nothing	N/2 All disks are written simultaneously

  Two , Disk array practice

RAID 0

  Verify that... Is installed

  Commands and formatting

/dev/md0: finger raid0 -n2： It refers to the need for two hard disks ,-l0： Refers to the type of raid0
/dev/sd[f-g]1: It refers to the area that needs several disks to do raid0

 

Mount

 RAID 0 Show details

 RAID 1

Naming and formatting

/dev/md1: finger raid1 -n2： It refers to the need for two hard disks ,-l1： Refers to the type of raid1
/dev/sd[f-g]2: It refers to the area that needs several disks to do raid1

  format

Mount

RAID 1 Show details

Input lsblk see

 RAID 5

Name and format

  format

Mount  

  see raid5, Information

  test ： Remove a copy etc The next disk , See if it will have an impact ,

 cat /proc/mdstat

 raid 10

establish RAID

  see

 

 

  summary

        RAID It has the advantage of fast reading and writing , Different at the same time RAID Level , Select according to data storage and access requirements RAUD, Generally speaking , A single server is very important , Not much disk , Use RAID1 It's very suitable , The main database of the database or storage server is RAID10, From the library is RAID5 perhaps RAID0,WEB The server , Without a lot of data , Use RAID5/RAID0, There are multiple monitors / In the case of application server , Use RAID5 perhaps RAID0 All can .