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A sector : The disc is divided into sectors , Each sector stores 512 Bytes of data , The smallest storage unit of a hard disk
Magnetic track : Concentric circles with different radii on the same disk , It is a circular track drawn by the magnetic head on the surface of the disk , Convenient data storage
cylinder : A cylindrical surface formed by the same radius of different disks , It consists of multiple tracks of the same radius circle

Hard disk storage capacity = Number of heads x Magnetic track ( cylinder ) Count × Sectors per channel × Bytes per sector (512 byte )

You can use a cylinder / The head sector uniquely locates each area on the disk

Hard disk interface type

IDE、SATA、SCSI、SAS、 Fibre channel

MBR（ Master bootstrap and partition table ）

1.MBR In the first physical sector of the hard disk , MBR It contains the main boot program and partition table of the hard disk
2.MBR in total 512 byte , front 446 The byte is the master boot record , The partition table is saved MBR The second in the sector 447-512 In bytes
3. The partition table has 4 Zone record area , The recording area of each zone accounts for 16 byte

Linux The hard disk in the computer 、 Devices such as partitions are represented as files

The partition represents

/dev/sda1
sd Express scsi equipment hd: Express IDE equipment
a: Indicates the number of hard disks .a,b,c
1： Indicates the number of partitions ,

Disk partition structure

On the hard disk Number of primary partitions Only 4 individual （1、2、3、4）

The number of primary and extended partitions is limited to 1~4

Only one extended partition can be created

First establish After expanding the partition , Can be divided into A logical partition

The ordinal number of the logical partition will always be from 5 Start , There is no limit to the number of logical partitions

File system type

XFS file system

File system for storing files and directory data （ Special partition ）
High performance log file system , Especially good at dealing with big files , Can support millions of TB Storage space
CenOS 7 The default file system used in the system fs The end file is usually the file system
Management document Manage disks

swap Exchange file system

by Linux Create a swap partition

It's usually physical memory 1.5 To 2 times

Linux Other supported file system types

EXT4、 FAT32、 NTFS、 LVM （ Cross disk ）

Disk management

View partition ：fdisk -l [ Disk device ]

Set partition ：fdisk [ Disk device ]

Device： Device file name of partition ;
Boot： Is it a bootstrap partition , If yes, there are “ * ” Number identification ;
Start： The starting position of the partition in the hard disk （ Cylinders ）;
End： The end of the partition on the hard disk （ Cylinders ）;
Blocks： Size of partition , With Blocks（ block ） In units of , The default block size is 1024 byte .
Id： The system corresponding to the partition ID Number ,82 yes swap ,83 Express Linux Default partition in （XFS or EXT4）,8e Express LVM Logic volume ;
System： Partition type

fdisk /dev/sdb/

Instructions for partitioning the hard disk

Instructions    effect
m   ： Get help menu
p   ： Check the zoning
n   ： New partition
d   ： Delete partition
t   ： Change zone type
w   ： Save the partition operation and exit
q   ： Exit directly without saving the partition operation
l ： Show all partition types （83 Common type 82swap 8e LVM fd raid Disk entire column ）

New hard disk operation

First click on virtual machine settings Click Add Follow the steps to the next step , Select the size you want to add , And save the path

First fdisk -l View disk information See if the disk you just added can be found

fdisk /dev/sdc Enter disk configuration , Prepare to configure disk

First configure a 10G Main partition

Press n Indicates a new partition p Represents the primary partition e For extended partition

Configure one more 15G Extended partition for

Create two more logical partitions One is 5G One is 8G

Press p Check the partition

take sdc6 Modified into swap Format

Finally save and exit

take sdc6 format

mkfs.xfs /dev/sdc6

take sdc6 mount /yunyun

Set up auto mount

stay /etc/fstab The file stores the static mount data of the file system .Linux Every time you start up , Will automatically read the contents of this file , Automatically mount the specified file system .

vim /etc/fstab