How to mount Linux system disk?

For Linux systems, the methods of mounting disks are actually similar, so this article takes the CentOS system as an example to introduce the Linux system disk mounting method, most of the previous The content comes from Tianyiyun’s forum.
1.Check the disk status
Use the command fdisk -l # to list all disk information

[root@qxyw ~]# fdisk -l

Disk /dev/xvda: 42.9 GB, 42949672960 bytes255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0008a9a5Device Boot          Start         End      Blocks   Id  System/dev/xvda1               1         523     4194304   82  Linux swap / Solaris
Partition 1 does not end on cylinder boundary./dev/xvda2   *         523        5222    37747712   83  Linux

Disk /dev/xvde: 322.1 GB, 322122547200 bytes255 heads, 63 sectors/track, 39162 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

2. Create a partition
fdisk /dev/xvde # Partition the xvde hard disk
n # Create a new partition
p # Create a primary partition (e is the extended partition)
1 # 1 means the first A primary partition
Enter # Start partitioning from the first cylinder
Enter # Indicates that the entire xvde is written into the first partition (if you need to divide the sdb into multiple partitions, enter + partition size at this time)
P # Check the created partition
w # Save and exit

[root@qxyw ~]# fdisk /dev/xvde
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x590ca8b1.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1First cylinder (1-39162, default 1): 
Using default value 1Last cylinder, +cylinders or +size{K,M,G} (1-39162, default 39162): 
Using default value 39162Command (m for help): p

Disk /dev/xvde: 322.1 GB, 322122547200 bytes255 heads, 63 sectors/track, 39162 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x590ca8b1Device Boot      Start         End      Blocks   Id  System/dev/xvde1               1       39162   314568733+  83  Linux

Command (m for help): w
The partition table has been altered!Calling ioctl() to re-read partition table.
Syncing disks.

3.Create the partition file system and format it Convert disk
# mkfs.ext4 /dev/xvde1 # Format xvde1 in ext4 format

[root@qxyw ~]# mkfs.ext4 xvde1
mke2fs 1.41.12 (17-May-2010)
Could not stat xvde1 --- No such file or directory

The device apparently does not exist; did you specify it correctly?[root@qxyw ~]# mkfs.ext4 /dev/xvde1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks19660800 inodes, 78642183 blocks3932109 blocks (5.00%) reserved for the super user
First data block=0Maximum filesystem blocks=4294967296
2400 block groups32768 blocks per group, 32768 fragments per group8192 inodes per group
Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624, 11239424, 20480000, 23887872, 71663616Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 25 mounts or180 days, whichever comes first.  Use tune2fs -c or -i to override.

4. Under the home directory Create the folder mysql and mount the device to /home/mysql.

[root@qxyw home]# mount /dev/xvde1 /home/mysql
[root@qxyw home]# df -h
Filesystem            Size  Used Avail Use% Mounted on/dev/xvda2             36G  2.4G   32G   7% /tmpfs                 3.9G     0  3.9G   0% /dev/shm/dev/xvde1            296G  191M  281G   1% /home/mysql

If there is a file in the original folder, the file will disappear after being mounted and the lost+found folder will appear. Don’t worry at this time. You can use the umount command to unmount it. .
The reason is this.
This involves the VFS (virtual file system) mechanism of Linux. After logging in, each directory and file you see is the VFS directory tree constructed in the memory when the kernel is loaded, instead of directly seeing the actual directory tree on the hard disk.
According to my rough understanding of , when you mount a device to a VFS mount point (such as /home), the system Point the mount point /home in VFS to the device you last mounted. Then when you access the mount point now, you will see the device you last mounted here. The previously mounted device is still there, but the mount point /home no longer points to the previous device. You can unmount the original device and mount it to a new mount point for access.

5.Write disk UUID to fstab

For Linux system Generally speaking, the partitions of disks xvda and The UUID information is written into the fstab file to bind the partition to the disk.
1) Obtain the UUID of the disk partition through blkid

[root@qxyw ~]# blkid
/dev/xvda1: UUID="5546dd0c-ef40-451b-b266-df8ef3a49967" TYPE="swap" 
/dev/xvda2: UUID="77fc0962-b3cf-400a-8903-0632e077fa09" TYPE="ext3" 
/dev/xvde1: UUID="1d17945b-c369-42de-85a8-47217d24d3e5" TYPE="ext4"

2) Add the disk information of xvde1 in the last line through vim /etc/fstab

#
# /etc/fstab
# Created by anaconda on Thu Jan 12 02:47:21 2017#
# Accessible filesystems, by reference, are maintained under '/dev/disk'# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info#
UUID=77fc0962-b3cf-400a-8903-0632e077fa09 /                       ext3    defaults        1 1UUID=5546dd0c-ef40-451b-b266-df8ef3a49967 swap                    swap    defaults        0 0tmpfs                   /dev/shm                tmpfs   defaults        0 0devpts                  /dev/pts                devpts  gid=5,mode=620  0 0sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
UUID=d17945b-c369-42de-85a8-47217d24d3e5 /home/mysql ext4 defaults      0 0

6. Transfer the contents under /var/lib/mysql/ to /home/mysql/, and create a mysql link under /var/lib/, The actual directory is actually /home/mysql

[root@qxyw /]# cd home[root@qxyw home]# mkdir mysql
[root@qxyw home]# mv /var/lib/mysql/* /home/mysql[root@qxyw home]# ln /home/mysql /var/lib/mysql

7. Verify it and check the disk usage through the df command. Then enter the mysql command to create the database test1... After execution, the database test1 will appear in the /home/mysql/ folder. In addition, use the df command to check the disk usage. You will find that the usage of /dev/xvde1 is increasing.

[root@qxyw mysql]# df
Filesystem           1K-blocks      Used Available Use% Mounted on/dev/xvda2            37155392   2417608  32850400   7% /tmpfs                  4018012         0   4018012   0% /dev/shm/dev/xvde1           309633052    217092 293687524   1% /home/mysql

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