Tag Archives: lvmresize

Increase LVM Partition in Linux

Some notes on increasing LVM partition in Linux.

Terminology

  • Physical Volume (PV): This can be created on a whole physical disk (think /dev/sda) or a Linux partition.
  • Volume Group (VG): This is made up of at least one or more physical volumes.
  • Logical Volume (LV): This is sometimes referred to as the partition, it sits within a volume group and has a file system written to it.
  • File System: A file system such as ext4 will be on the logical volume.

Increase or Expand Logical Volume

To increase/expand a logical volume (lv from here onward), it can be done without needing to reboot or experiencing any downtime on the system.

My volume group (vg here onward) is “debian-vg”; it contains all my lv’s.

root@debian:~# vgdisplay
  --- Volume group ---
  VG Name               debian-vg
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  8
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                5
  Open LV               5
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               39.76 GiB
  PE Size               4.00 MiB
  Total PE              10178
  Alloc PE / Size       7151 / 27.93 GiB
  Free  PE / Size       3027 / 11.82 GiB
  VG UUID               QPsbEO-d7Q4-OlbR-9BQL-4C1k-04oq-R8QcG6

As you can see above, the “Free PE / Size” indicates how much available to use to increase/expand a lv I have.

To look at the logical volumes, I use lvdisplay command.

 --- Logical volume ---
  LV Path                /dev/debian-vg/home
  LV Name                home
  VG Name                debian-vg
  LV UUID                61YQXT-wTDM-Fb66-1Fy0-U9dK-tHcn-Kzf1M8
  LV Write Access        read/write
  LV Creation host, time debian, 2018-06-11 10:03:17 -0400
  LV Status              available
  # open                 1
  LV Size                10.00 GiB
  Current LE             2560
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:4

My “home” logical volume is currently 10GB in size, indicated by “LV Size” above.

If I want to expand this to 12GB, I would issue the following:

root@debian:~# lvextend -L+2G /dev/debian-vg/home
  Size of logical volume debian-vg/home changed from 10.00 GiB (2560 extents) to 12.00 GiB (3072 extents).
  Logical volume debian-vg/home successfully resized.

Looking at lvdisplay output again, I see that it is now 12GB, but I need to expand the filesystem now.

 --- Logical volume ---
  LV Path                /dev/debian-vg/home
  LV Name                home
  VG Name                debian-vg
  LV UUID                61YQXT-wTDM-Fb66-1Fy0-U9dK-tHcn-Kzf1M8
  LV Write Access        read/write
  LV Creation host, time debian, 2018-06-11 10:03:17 -0400
  LV Status              available
  # open                 1
  LV Size                12.00 GiB
  Current LE             3072
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:4

This partition is ext4, so I will use resize2fs as below:

root@debian:~# resize2fs /dev/debian-vg/home
resize2fs 1.43.4 (31-Jan-2017)
Filesystem at /dev/debian-vg/home is mounted on /home; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 2
The filesystem on /dev/debian-vg/home is now 3145728 (4k) blocks long.

Note: If using xfs, use xfs_growfs in lieu of resize2fs

That should do it, now I can issue df -h and confirm that my /home partition is now 12GB.

root@debian:~# df -h
Filesystem                   Size  Used Avail Use% Mounted on
udev                         991M     0  991M   0% /dev
tmpfs                        201M   24M  177M  12% /run
/dev/mapper/debian--vg-root  7.4G  2.3G  4.7G  33% /
tmpfs                       1003M     0 1003M   0% /dev/shm
tmpfs                        5.0M     0  5.0M   0% /run/lock
tmpfs                       1003M     0 1003M   0% /sys/fs/cgroup
/dev/mapper/debian--vg-tmp   544M  924K  503M   1% /tmp
/dev/sda1                    236M   37M  187M  17% /boot
/dev/mapper/debian--vg-var   7.7G  2.5G  4.9G  34% /var
tmpfs                        201M     0  201M   0% /run/user/1000
/dev/mapper/debian--vg-home   12G   41M   12G   1% /home