How to extend LVM partition

LVM is a Logical Volume Manager, and it does not support extending partitions using a traditional extending procedure. LVM consists of physical volume, volume group, and logical volume, and the first one needs to be created, while the last two needs to be extended. Before extending an LVM partition, you should add either another physical or virtual disk to your setup. This guide presumes that the disk is already added. In the example, the new disk is referred to as a /dev/sdb with a size of 40GB. Login into your server console and type the following commands to identify the physical volume, volume group, and logical volume that needs to be extended.

# pvdisplay
--- Physical volume ---
PV Name /dev/sda1
VG Name rl
PV Size 38,41 GiB / not usable 2,00 MiB
Allocatable yes (but full)
PE Size 4,00 MiB
Total PE 9833
Free PE 0
Allocated PE 9833
PV UUID WE8Xbp-Fkuh-iLqN-LpzZ-QQrG-65BL-owKia1


# vgdisplay
--- Volume group ---
VG Name rl
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 38,41 GiB
PE Size 4,00 MiB
Total PE 9833
Alloc PE / Size 9833 / 38,41 GiB
Free PE / Size 0 / 0
VG UUID 6O96JD-ex54-dTH1-nFk3-gPYZ-xhWa-2OA9mo


# lvdisplay
--- Logical volume ---
LV Path /dev/rl/swap
LV Name swap
VG Name rl
LV UUID 2ceJdW-z2bf-jOfh-7Pre-v8HG-TOFj-q5Yogl
LV Write Access read/write
LV Creation host, time home.cph.sefnet.int, 2022-11-21 18:07:55 +0100
LV Status available
# open 2
LV Size <3,83 GiB
Current LE 980
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1

--- Logical volume ---
LV Path /dev/rl/root
LV Name root
VG Name rl
LV UUID M8Yoc9-sMpR-wRbA-ZKXr-5xMt-OQJK-csme7J
LV Write Access read/write
LV Creation host, time home.cph.sefnet.int, 2022-11-21 18:07:55 +0100
LV Status available
# open 1
LV Size 34,58 GiB
Current LE 8853
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0

The pvdisplay command lists the physical disk groups. Basically, you will need to create a new physical disk group consisting of the newly added disk, so do the following:

# pvcreate /dev/sdb
Physical volume "/dev/sdb" successfully created

After the physical disk group is created, we proceed with the extension of the volume disk group. In this example, we will extend the “rl” volume group. After you have identified the volume group you need to extend, do the following:

# vgextend rl /dev/sdb
Volume group "rl" successfully extended

Now we need to extend the logical volume. In this example, we will extend the /dev/rl/root logical volume. After you have identified the logical volume you need to extend, do the following:

# lvextend -l +100%FREE /dev/rl/root
Logical volume root successfully resized

The last step is to resize the file system, and depending on the filesystem format you have used under installation, you will need to use the appropriate command. To identify the correct file system, check your /etc/fstab file. In this example, the filesystem is formatted with xfs:

# xfs_growfs /dev/rl/root

Now you can confirm that the available free space is increased using the df -h command.