Theory + Experiment: Disk Management and File System---Comparative summary operation

One, disk basics

■ The physical structure of the hard disk

Disc: The hard disk has multiple discs, each with 2 sides
Magnetic head: one magnetic head on each side
■ Hard disk data structure
Sector: The disc is divided into multiple sectors, each sector stores 512 bytes of data
Track: Concentric circles with different radii on the same disc
Cylindrical surface: a cylindrical surface composed of different discs with the same radius

■ Disk storage capacity = number of heads × number of tracks (cylinders) × number of sectors per track × number of bytes per sector
■ Cylinder/head/sector can be used to uniquely locate each area on the
disk ■ Disk interface type

IDE, SATA, SCSI, SAS, Fibre Channel

1.2. MBR and disk partition representation

■ Master Boot Record (MBR)

MBR is located at the first physical sector of the hard disk
MBR contains the hard disk's master boot program and hard disk partition table
The partition table has 4 partition record areas, each of which occupies 16 bytes

■ In Linux, devices such as hard disks and partitions are represented as files
Insert picture description here

1.3, disk partition structure

■ The number of primary partitions in the hard disk is only 4
■ The serial numbers of primary and extended partitions are limited to 1~4
■ Extended partitions are then divided into logical partitions
■ The number of logical partitions will always start from 5.
Insert picture description here

1.4, file system type

■ xFS file system

Partition to store file and directory data
High-performance journal file system
The file system used by default in CentOS7 system
■ SWAP, swap file system
Create swap partition for Linux system

■ Other file system types supported by Linux

FAT16、FAT32、NTFS
EXT4、JFS…

2. Detect and confirm the new disk

2.1. Detect and confirm the new hard disk

■ fdisk command

View or manage disk partitions

fdisk -l [磁盘设备]
或
fdisk[磁盘设备]

■ Common commands in interactive mode

m、p、n、d、t、w、q
d ## Delete partition
m ## List manuals
n ## Add partition
p ## List partition
q ## Exit without saving
t ## Change the partition type
w ## Save and exit

[root@zk ~]# fdisk -l   ###查看硬盘的相关信息
Device      Boot      Start         End        Blocks   Id  System
/dev/sda1    *         2048       4196351     2097152   83  Linux
/dev/sda2            4196352     209715199   102759424  8e  Linux LVM

Device partition device name
Whether Boot is a boot partition, such as *
Start position (number of hard disk cylinders)
End end position (number of hard disk cylinders)
Blocks partition size is in blocks, the default block size is 1024 bytes
System ID number corresponding to ID partition, 7 means NTFS format, 81 means logical partition, 82 means SWAP, 83 means EXT4, 8e means LVM logical volume
System partition type

Three, create a file system

3.1, mkfs command

Create file system, format

mkfs -t 文件系统类型 分区设备

3.2, mkswap command

Create a swap file system

mkswap 分区设备

■ Example

[root@zk ~]# mkswap /dev/sdb5
[root@tx ~]# cat /proc/meminfo |grep Swap Total
[root@tx ~]# swapon /dev/sdb5
[root@tx ~]# cat /proc/meminfo | grep Swap Total
[root@tx ~]# swapoff /dev/sdb5

Four, mount and unmount the file system

4.1. Mount and unmount the file system

■ mount command

Mount the file system and ISO image to the specified folder

mount [-t类型] 存储设备挂载点目录
mount -o loop ISO 镜像文件挂载点目录

■ umount command

Unmount the mounted file system

umount 存储设备位置
umount 挂载点目录

4.2. Mount and unmount file system operations

Hard disk partition mounting and unmounting
Mounting and unmounting of optical disc devices
ISO image file mounting example
Unmount the file system

Unmount
Insert picture description here

4.3, set the automatic mounting of the file system

/etc/fstab configuration file
Contains file system records that need to be automatically mounted after booting

vi /etc/fstab

4.4, check disk usage

■ df command

df [选项] 文件

■ Example

[root@tx ~]# df -Th
Filesystem              Type      Size  Used Avail Use% Mounted on
/dev/mapper/centos-root xfs        82G  8.5G   74G  11% /
devtmpfs                devtmpfs  1.9G     0  1.9G   0% /dev
tmpfs                   tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs                   tmpfs     1.9G   12M  1.9G   1% /run
tmpfs                   tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/sr0                iso9660   4.3G  4.3G     0 100% /mnt
/dev/sda1               xfs       2.0G  146M  1.9G   8% /boot
tmpfs                   tmpfs     378M     0  378M   0% /run/user/0

Five, summary operation

1. Create a primary partition.
Insert picture description here

Create an extended partition.

Create a logical partition.

2. Mount (temporary)
mkfs.xfs /dev/sdb1. Change sdb1 to xfs and format it.

Insert picture description here

Then use df -Th to look at the mounting situation

3. Enter vi /etc/fstab mounting method (permanent)

4. Enter vi /etc/fstab to correct the mounting error

and then enter vi /etc/fstab

5. Permanent mount CD,
first hit temporary mount

, use df -Th to view
Insert picture description here
, enter vi /etc/fstab to

check if there is any problem with the mount