Linux Basics Tutorial 33-hard disk partitioning and mounting

Mount command

 In the Windows system, if you insert a USB flash drive, a mobile hard disk, an optical drive, etc., as long as it can be recognized by the Windows system, the system will automatically mount and add the drive letter, then we can access, and all of this is done by the system, the user does not need to do anything to use. In Linux, though, some Linux systems have already done some automatic mounts, but most of them need to be mounted manually. This function is done by the command Mount and the umount command.

Mount command

 The Mount command is primarily used to load the file system to a specified mount point. Its basic syntax is as follows:

mount [options] [device name] [mount point]

The common options are as follows:

Options	Description
-A,--all	Mount all file systems in the/etc/fstab file
-F,--fork	Often used with-A to increase mount speed when the system mounts a large number of NFS systems
-F,--fake	Often used for troubleshooting, does not perform a real mount operation, only simulates the mount process and is often used with-V
-N,--no-mtab	Do not write the load record to/etc/mtab, usually when the/etc directory is read-only
-R,--read-only	Mount the file as read-only mode, with-o ro
-W,--RW,--read-write	Mount the file as a readable writable mode, with-o RW, system default mode
-T,--types Vfstype	Specifies the type of file system to mount, and if you do not specify this option, the default is auto
-O,--options opts	Specify how mounts are mounted
-V,--version	Display version Information
-V,--verbose	Show more information

When using the mount command to mount, you need to confirm that the mount point must be an existing directory.

Where-T,--types commonly used file system formats are as follows:

File System Format	Description
Ext2	Common file system formats for Linux systems
Ext3	Common file system formats for Linux systems
Ext4	Common file system formats for Linux systems
iso9660	Cd-row disc standard File system format
Vfat	Windows FAT32 File System format
Xfs	Common file system formats for Linux systems, supported in CentOS7
Nfs	Network File System format
Ntfs	Windows NTFS file system format, requires a separate installation package
Auto	Automatically detect file system formats

Where-O,--options commonly used options are as follows:

Options	Description
Atuo	Allow use with-a
Noauto	Not allowed with-a
Defaults	Use default options: RW, suid, dev, exec, auto, Nouser, and Async
Ro	Mount in read-only mode
rw	Mount in read-write mode
Nouser	Prohibit a user (root) from mounting a file system
Users	Allow all users to mount and Unmount file systems
Owner	Allow non-root mount, but the user must have all permissions for the device
Loop	Mount in loop form

In Linux, there is a special device called loop device, which is a virtual block device formed by mapping normal files on the operating system. So we can create a mechanism for a virtual file system that exists in other files based on this device.

Umount command

The Umount function, in contrast to mount, is used primarily to unload a mounted file system, similar to deleting a USB flash drive in Windows, moving a hard disk, and so on. Its basic syntax is as follows

umount [options] [mount point]

The common options are as follows:

Options	Description
-A	Uninstall all file systems recorded in the/etc/mtab
-R	If it cannot be uninstalled, it is re-mounted as read-only
-D	If the uninstalled device is a loop device, release the loop device while uninstalling
-T Vfstype	Uninstalls only file systems of the specified type
-F	Forcibly uninstall

Hard Disk Partitioning command

? ? In Windows, if the system has increased the hard disk, can be recognized by the system, usually only need to select the corresponding hard disk in the Computer Management right-click to select the format. And how does Linux work? We introduce two formatted command fdisk and parted commands.

In practical applications, how to choose these two commands is determined by the capacity of the hard disk-if the hard disk capacity is less than 2TB, MBR is preferred, then use the fdisk command-if the hard disk capacity is greater than or equal to 2TB, you must select GPT, then use the parted command

FDISK command

The basic syntax is as follows:

fdisk [options] [device]

The common options are as follows:

Options	Description
-H	Display Help information
-L	Displays the partition table information for the specified device, which displays the records in/proc/partitions by default, if no device is specified
-V	Display version Information
-S partition	Displays the specified device partition size

The Fdisk menu is commonly described as follows:

menu item	Description
D	Delete Partition table
L	Show supported partition table types
M	displaying menus and help information
N	New Partition Table
P	Show partition information
Q	Exit does not save
V	Partition Table Check
W	Save partition table information and exit

parted command

The common syntax is as follows:

parted [options] [device] [command]

The common options are as follows:

Options	Description
-H,--help	Display Help information
-L,--list	Show partition table information for all devices
-V,--version	Display version Information
-S,--script	Automatic mode, no manual intervention required
-A Alignment-type	Partition alignment

Commonly used alignment methods are as follows:-none: select the minimum alignment based on the type of hard disk-cylinder: alignment based on the cylinder of the hard disk-optimal: select the optimal alignment based on the hard disk topology information

The common commands are as follows:

command	description
Help [command]	displays the helpful information for the specified command
mklabel label-type	Specify partition table type
Mkpart Part-type [fs-type] start end	create partition, start/end to start and end, default to MB
RM partition	Delete partition
Select Device	specify the device to edit
set partition flag state	set partition type and status
print	display partition table information
quit	exit

The common label-types are as follows:-bsd, dvh, gpt, loop, mac, msdos, pc98, sun The common part-types are as follows (must specify a type when creating a partition):-primary, logical Common extended fs-types are as follows:-ext2, ext3, ext4, fat32, ntfs, xfs common flags are as follows:-boot, root, swap, hidden, raid (software RAID), lvm (logical volume) Common states are as follows:-on, off

The starting and ending positions in the partition are represented by:

Start Position	End Position	Description
1	-1	Use full capacity
0%	100%	Use full capacity
0	30G	Use the space capacity of the front 30G
30G	100%	Use the remaining space capacity

formatting partitions

The MKFS command is all called Make filesystem, and the main purpose is to create a Linux file system.

MKFS command

Its common syntax format is as follows:

mkfs [-t fstype] [fs-options] [device]

The common options are as follows:

Options	Description
-T Fstype	You can view the Fs-type in parted and default to ext2 if not specified
-C	Check the partition for bad paths before creating the file system
-L filename	Read bad message from file
-V	Show more information

MKE2FS command

? ? Used to create the Ext2,ext3,ext4 file system. The common syntax is as follows:

mke2fs [options]

The common options are as follows:

Options	Description
-B block-size	Set the amount of space per data chunk to support 1024B, 2048B, 4096B
-C	Check the partition for bad paths before creating the file system
-F	Forcing the file system to be created
-j	Creating a file system of the ext3 type
-Q	Silent mode
-T Fs-type	Specifies the type of file system created
-V	Show detailed procedures

mke2fs is equivalent to mke2fs.ext2 / mke2fs.ext3 / mke2fs.ext4.

MKFS.XFS command

? ? Used to create the XFS file system (CentOS 7 Default file system). The common syntax is as follows:

mkfs.xfs [options] [device]

The common options are as follows:

Options	Description
-B block-size	Set the amount of space per data chunk, default is 4KiB, minimum is 512, 64KiB Max
-F	Forcibly overwrite a file system that already exists
-Q	Silent mode

Example

1. Mount the ISO image file

[[email protected] ~] # ll * .iso
-rw-rw-r--. 1 root root 4470079488 June 20 21:04 CentOS-7.5-x86_64-DVD-1804.iso
# Create a mount point
[[email protected] ~] # mkdir -p / tmp / CDROM

[[email protected] ~] # mount -t iso9660 -o loop ~ / CentOS-7.5-x86_64-DVD-1804.iso / tmp / CDROM /
mount: / dev / loop2 is write-protected and will be mounted read-only

[[email protected] ~] # ll / tmp / CDROM /
Total dosage 678
-rw-rw-r-- 1 root root 14 May 2 19:28 CentOS_BuildTag
drwxr-xr-x 3 root root 2048 May 4 04:34 EFI
-rw-rw-r-- 1 root root 227 Aug 30 2017 EULA
-rw-rw-r-- 1 root root 18009 December 10 2015 GPL
drwxr-xr-x 3 root root 2048 May 4 04:44 images
drwxr-xr-x 2 root root 2048 May 4 04:34 isolinux
drwxr-xr-x 2 root root 2048 May 4 04:34 LiveOS
drwxrwxr-x 2 root root 655360 May 4 04:52 Packages
drwxrwxr-x 2 root root 4096 May 4 04:54 repodata
-rw-rw-r-- 1 root root 1690 December 10 2015 RPM-GPG-KEY-CentOS-7
-rw-rw-r-- 1 root root 1690 December 10 2015 RPM-GPG-KEY-CentOS-Testing-7
-r--r--r-- 1 root root 2883 May 4 04:55 TRANS.TBL

# View mount point
[[email protected] ~] # df -h
File System Capacity Used Available Used% Mount Point
/ dev / sda2 275G 20G 255G 8% /
/ dev / sda1 500M 9.8M 490M 2% / boot / efi
/ dev / sdb1 15T 4.2G 15T 1% / home / data
/ dev / loop2 4.2G 4.2G 0 100% / tmp / CDROM

2. Unloading mount point

[[email protected] ~] # umount / dev / loop2

[[email protected] ~] # ll / tmp / CDROM /
Total dosage 0

3. fdisk create partition, format and Mount

[[email protected] home] # fdisk -l / dev / sdb
Disk / dev / sdb: 4294 MB, 4294967296 bytes, 8388608 sectors
Units = sector of 1 * 512 = 512 bytes
Sector size (logical / physical): 512 bytes / 512 bytes
I / O size (minimum / optimal): 512 bytes / 512 bytes

[[email protected] home] # fdisk / dev / sdb
Welcome to fdisk (util-linux 2.23.2).

Changes stay in memory until you decide to write the changes to disk.
Think twice before using the write command.

Device does not contain a recognized partition table
Create a new DOS disk label with the disk identifier 0xa8afbc5f.

Command (enter m for help): m
Command operation
   a toggle a bootable flag
   b edit bsd disklabel
   c toggle the dos compatibility flag
   d delete a partition
   g create a new empty GPT partition table
   G create an IRIX (SGI) partition table
   l list known partition types
   m print this menu
   n add a new partition
   o create a new empty DOS partition table
   p print the partition table
   q quit without saving changes
   s create a new empty Sun disklabel
   t change a partition ‘s system id
   u change display / entry units
   v verify the partition table
   w write table to disk and exit
   x extra functionality (experts only)
Command (enter m for help): n
Partition type:
   p primary (0 primary, 0 extended, 4 free)
   e extended
Select (default p): p
Partition number (1-4, default 1): 2
Starting sector (2048-8388607, default is 2048):
Will use the default value of 2048
Last sector, + sector or + size {K, M, G} (2048-8388607, default is 8388607):
Will use the default value of 8388607
Partition 2 is set to Linux type and size is set to 4 GiB

Command (enter m for help): w
The partition table has been altered!

Calling ioctl () to re-read partition table.
Disk syncing.

[[email protected] home] # fdisk -l / dev / sdb

Disk / dev / sdb: 4294 MB, 4294967296 bytes, 8388608 sectors
Units = sector of 1 * 512 = 512 bytes
Sector size (logical / physical): 512 bytes / 512 bytes
I / O size (minimum / optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xe0dcbc1d

   Device Boot Start End Blocks Id System
/ dev / sdb2 2048 8388607 4193280 83 Linux

# Format the created partition
[[email protected] home] # mkfs -v -t ext4 / dev / sdb2
mke2fs 1.42.9 (28-Dec-2013)
fs_types for mke2fs.conf resolution: ‘ext4’
File system label =
OS type: Linux
Block size = 4096 (log = 2)
Block size = 4096 (log = 2)
Stride = 0 blocks, Stripe width = 0 blocks
262144 inodes, 1048320 blocks
52416 blocks (5.00%) reserved for the super user
First data block = 0
Maximum filesystem blocks = 1073741824
32 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
    32768, 98304, 163840, 229376, 294912, 819200, 884736

Allocating group tables: complete
Writing to inode table: complete
Creating journal (16384 blocks): completed
Writing superblocks and filesystem accounting information: complete

# Create a mount point
[[email protected] home] # mkdir -p / home / MountDisk

# Add mount information to / etc / fstab
[[email protected] ~] # echo "/ dev / sdb2 / home / MountDisk ext4 defaults 0 0" >> / etc / fstab

# Mount the hard disk and view the mount point
[[email protected] ~] # mount -a && df -h
File System Capacity Used Available Used% Mount Point
/ dev / sda6 19G 4.8G 15G 25% /
/ dev / sda1 1014M 281M 734M 28% / boot
/ dev / sda2 8.0G 76M 8.0G 1% / home
/ dev / sda3 8.0G 1.2G 6.9G 15% / var
/ dev / sdb2 3.9G 16M 3.7G 1% / home / MountDisk

4, parted creating partitions, formatting, and mounting

[[email protected] ~] # parted / dev / sdb
GNU Parted 3.1
Use / dev / sdb
Welcome to GNU Parted! Type ‘help’ to view a list of commands.
(parted) print Model: VMware, VMware Virtual S (scsi)
Disk / dev / sdb: 4295MB
Sector size (logical / physical): 512B / 512B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system logo
# Set partition type
(parted) mklabel gpt

Warning: The existing disk label on / dev / sdb will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes / Yes / No / No? Yes
# Set partition size
(parted) mkpart primary 1 -1
# Save and exit
(parted) quit
Information: You may need to update / etc / fstab.

[[email protected] ~] # parted -l
Model: VMware, VMware Virtual S (scsi)
Disk / dev / sda: 42.9GB
Sector size (logical / physical): 512B / 512B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system logo
 1 1049kB 1075MB 1074MB primary xfs boot
 2 1075MB 9665MB 8590MB primary xfs
 3 9665MB 18.3GB 8590MB primary xfs
 4 18.3GB 42.9GB 24.7GB extended
 5 18.3GB 22.6GB 4295MB logical linux-swap (v1)
 6 22.6GB 42.9GB 20.4GB logical xfs


Model: VMware, VMware Virtual S (scsi)
Disk / dev / sdb: 4295MB
Sector size (logical / physical): 512B / 512B
Partition Table: gpt
Disk Flags:

Number Start End Size File system Name logo
 1 1049kB 4294MB 4293MB ext4 primary

# Format the created partition
[[email protected] ~] # mkfs.xfs -f / dev / sdb1
meta-data = / dev / sdb1 isize = 512 agcount = 4, agsize = 262016 blks
         = sectsz = 512 attr = 2, projid32bit = 1
         = crc = 1 finobt = 0, sparse = 0
data = bsize = 4096 blocks = 1048064, imaxpct = 25
         = sunit = 0 swidth = 0 blks
naming = version 2 bsize = 4096 ascii-ci = 0 ftype = 1
log = internal log bsize = 4096 blocks = 2560, version = 2
         = sectsz = 512 sunit = 0 blks, lazy-count = 1
realtime = none extsz = 4096 blocks = 0, rtextents = 0

# Create a mount point
[[email protected] home] # mkdir -p / home / MountDisk

# Add mount information to / etc / fstab
[[email protected] ~] # echo "/ dev / sdb1 / home / MountDisk xfs defaults 0 0" >> / etc / fstab

# Mount the hard disk and view the mount point
[[email protected] ~] # mount -a; df -h -T
File System Type Capacity Used Available Used% Mount Point
/ dev / sda6 xfs 19G 4.8G 15G 25% /
/ dev / sda1 xfs 1014M 281M 734M 28% / boot
/ dev / sda2 xfs 8.0G 76M 8.0G 1% / home
/ dev / sda3 xfs 8.0G 1.2G 6.9G 15% / var
/ dev / sdb1 xfs 4.0G 33M 4.0G 1% / home / MountDisk 

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Linux Basics Tutorial 33-hard disk partitioning and mounting