• Experimental environment

  Operating system type rhel6.5
  Virtual machine of KVM type

• It is important to note that the root partition must be mounted using an extensible LVM volume group

• Use the command df -h to view

[root@server6 ~]# df -h
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root   18G  9.4G  7.1G  57% /
tmpfs                         487M     0  487M   0% /dev/shm
/dev/vda1                     485M   33M  427M   8% /boot

• First you need to add a hard disk
  

• Use the command to view the newly added hard disk with the size of 8G;

[root@server6 ~]# fdisk  -l

• Key contents
• To execute the partition command, you need to adjust the type to 8e

[root@server6 ~]# fdisk  -cu /dev/vdc 
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xadcf4a9d.
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)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First sector (2048-16777215, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-16777215, default 16777215): 
Using default value 16777215

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)

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

Calling ioctl() to re-read partition table.
Syncing disks.

• Notify kernel to read partition table again

[root@server6 ~]# partx /dev/vdc
# 1:      2048- 16777215 ( 16775168 sectors,   8588 MB)
# 2:         0-       -1 (        0 sectors,      0 MB)
# 3:         0-       -1 (        0 sectors,      0 MB)
# 4:         0-       -1 (        0 sectors,      0 MB)

• First make 'Physical Volume'

[root@server6 ~]# pvcreate /dev/vdc1 
  Physical volume "/dev/vdc1" successfully created

• Use the command pvs to view
  
• Add the made ones to the volume group

[root@server6 ~]# vgextend VolGroup /dev/vdc1 
  Volume group "VolGroup" successfully extended

• View the size change of volume group through the command vgs
  
• Expand logical volume group boundaries

[root@server6 ~]# lvextend -L +8G /dev/VolGroup/lv_root 
  Extending logical volume lv_root to 25.61 GiB
  Insufficient free space: 2048 extents needed, but only 2047 available
[root@server6 ~]# lvextend -l +2047 /dev/VolGroup/lv_root 
  Extending logical volume lv_root to 25.60 GiB
  Logical volume lv_root successfully resized

• Perform boundary expansion for logical volume groups

[root@server6 ~]# resize2fs /dev/VolGroup/lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/VolGroup/lv_root is mounted on /; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 2
Performing an on-line resize of /dev/VolGroup/lv_root to 6711296 (4k) blocks.
The filesystem on /dev/VolGroup/lv_root is now 6711296 blocks long.

• See the change of final result through df-h

[root@server6 ~]# df -h
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root   26G  9.4G   15G  40% /
tmpfs                         487M     0  487M   0% /dev/shm
/dev/vda1                     485M   33M  427M   8% /boot

• Screenshot of size comparison before and after