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How to resize a logical volume

Ricardo Aguilar
  • Updated

Introduction

This article will help you to resize a logical volume.

 

Procedure

 

First, you will want to view the mount point associated with a logical drive and the current reported size.

View the mount point associated with a logical drive and the current reported size.

 

You can use the df command to see the mount point that is associated with a logical drive and the current reported size:

 

[cptech@server ~]# 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/sda1 477M 125M 327M 28% /boot

/dev/mapper/centos-home  860G 72M 816G 1% /home
       
[cptech@server ~]#

 

See the total hard disk/s size and partitions 

 

You can utilize fdisk to see the total hard disk size and partitions. You can also use fdisk to determine which partition is being used for a logical volume. When you run fdisk, you will see that the partition is Linux LVM.

 

[cptech@server ~]# fdisk -l

Disk /dev/sda: 999.7 GB, 999653638144 bytes

255 heads, 63 sectors/track, 121534 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: 0x00031533

 

Device Boot Start End Blocks Id System

/dev/sda1 * 1 64 512000 83 Linux

Partition 1 does not end on cylinder boundary.

/dev/sda2 64 121535 975711232 8e Linux LVM

 

You can also use the lvs or pvs commands to see the partition associated with a logical volume.

 

[cptech@server ~]# lvs -o +devices /dev/mapper/dev/mapper/centos-home

  LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Devices

  home centos -wi-ao---- 872.88g /dev/sda2(12800)

[cptech@server ~]#



[cptech@server ~]# pvs

  PV VG Fmt Attr PSize PFree

  /dev/sda2 centos lvm2 a-- 930.51g 0

 

lvextend

 

The logical volume can be increased by using the lvextend command.

For example, if you want to increase a logical volume by 5 gigabytes, you can type the following:

 

[cptech@server ~]# lvextend -L +5G /dev/mapper/centos-home

Extending logical volume home to 865.00 GB

Logical volume successfully resized

 

If you want to increase it to a specific value, you can type the following instead:

 

lvextend -L870G /dev/mapper/centos-home

 

If you run df again, you will notice that the file system doesn’t seem to detect the correct size.

 

[cptech@server ~]# 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/sda1 477M 125M 327M 28% /boot

/dev/mapper/centos-home   860G 72M 816G 1% /home
                   

 

xfs_growfs, resize2fs, resize4fs

 

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

 

You can type the following if you are using xfs:

 

xfs_growfs /home

 

Notice that you will need to specify /home(mount point), which is associated with /dev/mapper/centos-home

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