Resizing the file system size is an important task of Linux admin’s profile. In Linux , LVM(Logical Volume Manager) provides the facility to increase and reduce the file system size. In this tutorial we will discuss the practical examples of lvextend and will learn how to extend LVM partition on the fly using lvextend command.

Scenario : Suppose we have a LVM partition(/home) and running out of space and want to extend or increase file system size. So to increase the size of the file system first we must see whether in volume group has free space or not. If the Volume group has free space then use the below steps :

Step:1 Type ‘ df -h’ command to list the file system

Run the “df -h” command followed by the file system to view total ,used and available disk space

[root@cloud home]# df -h /home/
 Filesystem            Size  Used Avail Use% Mounted on
 /dev/mapper/vg_cloud-LogVol00
                       9.7G  9.2G     0 100% /home

As we can see /home is 100 % utilized.

Step:2 Now check whether free space is available space in the volume group

To display volume group details, execute the vgdisplay command followed by volume group name,

# vgdisplay < Volume-Group-Name>

[root@cloud home]# vgdisplay vg_cloud
   --- Volume group ---
 VG Name                      vg_cloud
 System ID
 Format                       lvm2
 Metadata Areas               1
 Metadata Sequence No         4
 VG Access                    read/write
 VG Status                    resizable
 MAX LV                       0
 Cur LV                       3
 Open LV                      3
 Max PV                       0
 Cur PV                       1
 Act PV                       1
 VG Size                      27.01 GiB
 PE Size                      4.00 MiB
 Total PE                     6915
 Alloc PE / Size              5256 / 20.53 GiB
 Free  PE / Size              1659 / 6.48 GiB
 VG UUID                      1R89GB-mIP2-7Hgu-zEVR-5H02-7GdB-Ufj7R4

Step:3 Use lvextend command to increase the size.

Run below lvextend command to extend the file system,

[root@cloud ~]# lvextend -L +2G /dev/mapper/vg_cloud-LogVol00
     Extending logical volume LogVol00 to 11.77 GiB
     Logical volume LogVol00 successfully resized

Above command will extend the file system size by 2GB. You can also specify the size in MB , just replace G with M.

Step:3 Run the resize2fs command

In above step we have executed the lvextend command to extend the file system size by 2 GB but still the file system is not updated, so execute the following resize2fs command

[root@cloud ~]# resize2fs /dev/mapper/vg_cloud-LogVol00

Step:4 Use df command and verify /home size .

Re-run the df -h command followed by /home file system, now we can see that file system has been extended by 2 GB, before the extension size was 10 GB

[root@cloud ~]# df -h /home/
 Filesystem            Size  Used Avail Use% Mounted on
 /dev/mapper/vg_cloud-LogVol00
                        12G  9.2G  1.9G  84% /home