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How to resize a logical volume

Ricardo Aguilar
  • Updated

Introduction

This article provides a brief overview of resizing a logical volume.

Please note that cPanel support cannot assist you with resizing a logical volume. We recommend you seek assistance from a qualified system administrator to resize any disk.

 

Procedure

Incorrectly modifying a volume can destroy all data on the volume. It is strongly recommended that you back up your data to an off-server location before attempting to resize a volume.

Please note that, in the provided examples, "centos" is the volume group, "xvda" is the existing disk, and "xvdb" is the new disk. The volume group and disks on your server may be different.

  1. SSH into your server as the 'root' user.
  2. Review the size and mount point associated with the logical volume to alter. 
    [root@server ~]cPs# df -h
    Filesystem               Size   Used  Avail  Use%  Mounted on
    /dev/mapper/centos-root   50G    23G    24G   49%  /
    tmpfs                    3.8G      0   3.8G    0%  /dev/shm
    /dev/xvda1               477M   125M   327M   28%  /boot
    /dev/mapper/centos-home  860G    72M   816G    1%  /home
    /dev/loop0               1.6G   2.6M   1.5G    1%  /tmp
    [root@server ~]cPs#
  3. Review the physical disk information. 
    [root@server ~]cPs# lsblk
    NAME                 MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
    xvda                 202:0    0  40G  0 disk 
    └─xvda1              202:1    0  40G  0 part /
    └─xvda2              202:2    0 960G  0 part
      └─centos-root      253:1    0  50G  0 lvm  /
      └─centos-home      253:2    0 860G  0 lvm  /home
    loop0                  7:0    0 1.6G  0 loop /var/tmp
    xvdb                 232:16   0  50G  0 disk
    [root@server ~]cPs#
  4. If the volume will be extended using another disk:
    1. Initialize the new disk using the pvcreate command. 
      pvcreate /dev/xvdb
    2. Identify the volume group to add the new disk to with the vgs command. 
      [root@server ~]cPs# vgs
        VG      #PV #LV #SN Attr        VSize   VFree
        centos    1   2   0 -wi-ao----  960g    50g
    3. Use the vgextend command to extend the volume group to the new disk. 
      vgextend centos /dev/xvdb
  5. Use the lvextend command to expand the logical volume. 
    lvextend -l +100%FREE /dev/mapper/centos-root

Please note that for the file system to detect the new logical volume size, you will need to run xfs_growfs for xfs file systems or either resize2fs or resize4fs for ext2/ext3/ext4 file systems to expand and resize the file system.

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