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Resize Ubuntu LVM in TrueNAS Bhyve

This post summarizes the steps required to increase the partition size of Ubuntu 20.04 Server running as VM, with LVM volume management.

Problem

Ubuntu 20.4 VM has no space left. It uses LVM.

Context

TrueNAS 12 with bhyve, Ubuntu 20.04 Server installed as VM with all default settings.

Steps

  1. Resize VM’s zvol to desired size (e.g. 20G) at TrueNAS Web UI.

  2. Reboot VM, see if disk (e.g. /dev/sda) is resized with lsblk:

$ lsblk
NAME                      MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
loop0                       7:0    0 55.4M  1 loop /snap/core18/2128
loop1                       7:1    0 61.9M  1 loop /snap/core20/1242
loop2                       7:2    0 70.3M  1 loop /snap/lxd/21029
loop3                       7:3    0 55.5M  1 loop /snap/core18/2253
loop4                       7:4    0 32.5M  1 loop /snap/snapd/13640
loop5                       7:5    0 32.3M  1 loop /snap/snapd/12704
loop6                       7:6    0 67.2M  1 loop /snap/lxd/21835
sda                         8:0    0   20G  0 disk 
├─sda1                      8:1    0  512M  0 part /boot/efi
├─sda2                      8:2    0    1G  0 part /boot
└─sda3                      8:3    0  8.5G  0 part 
  └─ubuntu--vg-ubuntu--lv 253:0    0  8.5G  0 lvm  /

  1. Extend /dev/sda3 using cfdisk, don’t forget to call write before quitting. Check lsblk and make sure /dev/sda3 is increased in size.

  2. Extend the physical volume (pv):

sudo pvresize /dev/sda3

## Sample output:
#  Physical volume "/dev/sda3" changed
#  1 physical volume(s) resized or updated / 0 physical volume(s) not resized
  1. Extend the logical volume (lv):
# find it first with:
sudo lvdisplay | grep "LV Path"

## Sample output:
# LV Path         /dev/ubuntu-vg/ubuntu-lv

# now resize
sudo -E lvresize -l +100%FREE /dev/ubuntu-vg/ubuntu-lv

## Sample output:
#   Size of logical volume ubuntu-vg/ubuntu-lv changed from <8.50 GiB (2175 extents) to <18.50 GiB (4735 extents).
#   Logical volume ubuntu-vg/ubuntu-lv successfully resized.

  1. lsblk should output the same size for /dev/sda3 and the LVM logical volume. sudo lvdisplay should also report the increased size. But df -h still reports the old size on the root (/) mount point

  2. Increase the partition on top of the logical volume

sudo resize2fs /dev/ubuntu-vg/ubuntu-lv

## Sample output:
# resize2fs 1.45.5 (07-Jan-2020)
# Filesystem at /dev/ubuntu-vg/ubuntu-lv is mounted on /; on-line resizing required
# old_desc_blocks = 2, new_desc_blocks = 3
# The filesystem on /dev/ubuntu-vg/ubuntu-lv is now 4848640 (4k) blocks long.
  1. Now df -h should report increased size on the root (/) mount point.

Sources

2021-11-21