LVM Resize

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Resizing a partition is extremely easy to do with LVM as it can be done on the fly with no downtime needed. You can perform it on a mounted volume without interruption. In order to increase the size of a logical volume, the volume group that it is in must have free space available.

To view the free space of your volume group, run vgdisplay command as shown below and look at the “Free PE / Size” field.

┌(foo@bar)─(07:44 PM Sun Nov 25)─(~)
└> sudo vgdisplay
 --- Volume group ---
 VG Name               vg_sys
 System ID
 Format                lvm2
 Metadata Areas        2
 Metadata Sequence No  6
 VG Access             read/write
 VG Status             resizable
 MAX LV                0
 Cur LV                3
 Open LV               2
 Max PV                0
 Cur PV                2
 Act PV                2
 VG Size               20.74 GiB
 PE Size               4.00 MiB
 Total PE              5309
 Alloc PE / Size       4030 / 15.74 GiB
 Free  PE / Size       1280 / 5.00 GiB
 VG UUID               VvG6Sp-wIgb-LTh0-szdU-s9R1-a6K9-qHassI

In this example we have 5GB of free space in the volume group, as shown by “Free PE / Size 1280 / 5.00 GiB”.

Note: If you do not have any or enough free space in the volume group, you will first need to expand the volume group to complete the resize. Alternatively if you have multiple LVM partitions, you could shrink a different logical volume first to create space within the volume group.

Now that we have confirmed there is space free within the volume group, confirm the name of the logical volume you want to increase as well as how much space you plan on adding. The below lvdisplay command will show all logical volumes and their current size. It will also show the volume group that the logical volume is a member of, so ensure that the correct volume group has been checked for enough space with vgdisplay as previously mentioned to prevent trying to increase a logical volume that is inside some other volume group.

As shown in the example below, we are going to be working with the logical volume “lv_var” which is in volume group “vg_sys”, the volume group we saw in vgdisplay. In this example we only have just the one volume group, but you may have more so you need to check.

┌(foo@bar)─(07:46 PM Sun Nov 25)─(~)
└> sudo lvdisplay
 --- Logical volume ---
 LV Path                /dev/vg_sys/lv_var
 LV Name                lv_var
 VG Name                vg_sys
 LV UUID                7PNgg2-ZmnG-a26g-zRoT-PRVM-RDc1-oq6J4M
 LV Write Access        read/write
 LV Creation host, time bar, 2018-11-25 07:50:25 +1000
 LV Status              available
 # open                 0
 LV Size                5.00 GiB
 Current LE             1280
 Segments               1
 Allocation             inherit
 Read ahead sectors     auto
 - currently set to     256
 Block device           253:2

Now it’s time to expand the logical volume. In the below example we are using the -L flag to increase by a size specified (M for Megabytes, G for Gigabytes, T for Terabytes). You can alternatively remove the + to increase to the amount specified rather than by the amount specified.

┌(foo@bar)─(07:48 PM Sun Nov 25)─(~)
└> sudo lvextend -L+5G /dev/vg_sys/lv_var
 Rounding size to boundary between physical extents: 4.90 GiB
 Size of logical volume vg_sys/lv_var changed from 5.00 GiB (1280 extents) to 10.00 GiB (2560 extents).
 Logical volume lv_var successfully resized

The above command will increase the logical volume /dev/vg_sys/lv_var by 5GB. Currently it is already 5GB so this will increase it to a total of 10GB. You could achieve the same with lvextend -L 10G /dev/vg_sys/lv_var which will increase the logical volume to 10GB as well, as this is what was specified with no +. Alternatively if you instead want to just use all free space in the volume group rather than specifying a size to increase to, run lvextend -l +100%FREE /dev/vg_sys/lv_var.

We can run the below lvdisplay command shown below to check that the extend completed as expected.

┌(foo@bar)─(07:50 PM Sun Nov 25)─(~)
└> sudo vgdisplay
 --- Logical volume ---
 LV Path                /dev/vg_sys/lv_var
 LV Name                lv_var
 VG Name                vg_sys
 LV UUID                7PNgg2-ZmnG-a26g-zRoT-PRVM-RDc1-oq6J4M
 LV Write Access        read/write
 LV Creation host, time bar, 2018-11-25 07:50:25 +1000
 LV Status              available
 # open                 0
 LV Size                10.00 GiB
 Current LE             2560
 Segments               1
 Allocation             inherit
 Read ahead sectors     auto
 - currently set to     8192
 Block device           253:2

Now that the logical volume has been extended, we can resize the file system. This will extend the file system so that it takes up the newly created space inside the logical volume. The command may differ depending on the type of file system you are using.

  • Ext3/4
resize2fs /dev/vg_sys/lv_var
  • XFS
xfs_growfs /dev/vg_sys/lv_var

Double check that everything is sized as you expected by running df -h.

┌(foo@bar)─(07:51 PM Sun Nov 25)─(~)
└> df -h
Filesystem                  Size  Used Avail Use% Mounted on
/dev/mapper/vg_sys-lv_root  9.8G  1.4G  8.5G  14% /
devtmpfs                    908M     0  908M   0% /dev
tmpfs                       914M     0  914M   0% /dev/shm
tmpfs                       914M  8.6M  905M   1% /run
tmpfs                       914M     0  914M   0% /sys/fs/cgroup
/dev/sda1                   511M  156K  402M  20% /boot/efi
/dev/mapper/vg_sys-lv_var    10G   33M   10G   1% /var

See more tips and how-to's in our Linux , Networking , and ZFS sections.