Proxmox Backup Server PBS enlarge root disk

How to enlarge an EXT4 or LVM disk on an PBS Proxmox VM

Quick TL;DR Guide

1. First resize the disk in Proxmox
2. Then in the PBS VM terminal:
   parted /dev/sdX (probably a)  example 

   parted /dev/sda

   print / yes to fix / resizepart Y (probably 1)
   quit
3. resize2fs /dev/sdXY
4. df -h

Longer Guide with Explanation

First resize the disk in Proxmox:

At this point you need to START the PBS VM and enter the shell as root follow the below instractions.

fdisk -l

should show which disks are there.

Disk /dev/sda: 50 GiB, 53687091200 bytes, 104857600 sectors
Disk model: QEMU HARDDISK
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

Device       Start       End   Sectors  Size Type
/dev/sda1       34      2047      2014 1007K BIOS boot
/dev/sda2     2048   1050623   1048576  512M EFI System
/dev/sda3  1050624 104855551 103804928 31.5G Linux LVM

Disk /dev/mapper/pbs-swap: 3.82 GiB, 4106223616 bytes, 8019968 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/pbs-root: 27.67 GiB, 49039802368 bytes, 95780864 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

If you get this message which seems like an error, the resize in Proxmox worked:

GPT PMBR size mismatch (167772159 != 314572799) will be corrected by write.
The backup GPT table is not on the end of the device. This problem will be corrected by write.

The example above is resizing from 30 GB to 50 GB.

Now we still have to resize the file system from inside the PBS VM cli terminal :

lsblk

You should see something like the below.

NAME         MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda            8:0    0   50G  0 disk
├─sda1         8:1    0 1007K  0 part
├─sda2         8:2    0  512M  0 part
└─sda3         8:3    0 31.5G  0 part
  ├─pbs-swap 252:0    0  3.8G  0 lvm  [SWAP]
  └─pbs-root 252:1    0 27.7G  0 lvm  /

The run the below command to resize the sda3

lvextend -l +100%FREE /dev/mapper/pbs-root
resize2fs /dev/mapper/pbs-root

Check that root disk resize all free space

df -h

Output should be something like this.

Filesystem                        Size     Used   Avail    Use%   Mounted on
udev                                 3.9G      0         3.9G     0%      /dev
tmpfs                               795M    720K   794M    1%      /run
/dev/mapper/pbs-root    45G      26G     18G      59%    /
tmpfs                               3.9G      0          3.9G     0%     /dev/shm
tmpfs                               5.0M     0          5.0M    0%     /run/lock
tmpfs                               795M    0         795M    0%    /run/user/0

Now your PBS root disk is resize and have free space.

---

If you find this helpful or not please leave a comment.

Ins0mniA