🖥️ Ubuntu Virtual Machine Disk Expansion Runbook

This guide documents how to increase the disk size of an Ubuntu virtual machine hosted in Proxmox. It covers:

⚡ Quick Guide

Before choosing a workflow, identify your disk layout:

sudo lsblk
If you see… Example Use…
LVM volumes (ubuntu--vg-ubuntu--lv, /dev/mapper/...) /dev/sda3 → PV → VG → LV Path A: LVM Expansion
A single root partition (/dev/sda1, /dev/vda1) with no LVM /dev/vda1 mounted on / Path B: Non‑LVM Expansion

1️⃣ Increase the Virtual Machine Disk in Proxmox

Step Action Notes
1 Shut down the VM Ensure the VM is powered off
2 Go to Hardware tab Select the VM in Proxmox
3 Select the disk → Disk Action → Resize Enter the size increment in GiB
4 Click Resize Disk Wait for the operation to complete

⚡ Do not boot the VM until the resize is finished.

2️⃣ Expand the Disk Inside Ubuntu

After booting the VM, follow either Path A (LVM) or Path B (Non‑LVM).

🟩 Path A — LVM-Based Root Filesystem Expansion

(Use this if your root filesystem is on LVM.)

A.1 Verify Disk Layout

sudo lsblk

Example:

sda
├─sda1
├─sda2
└─sda3  → LVM PV
   └─ubuntu--vg-ubuntu--lv  → root filesystem

A.2 Grow the Partition

sudo growpart /dev/sda 3

A.3 Resize the Physical Volume

sudo pvresize /dev/sda3

A.4 Extend the Logical Volume

sudo lvextend -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv

A.5 Resize the Filesystem

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

A.6 Verify the New Size

df -h

🟦 Path B — Non‑LVM Root Filesystem Expansion

(Use this if your root filesystem is a normal partition like /dev/vda1 or /dev/sda1.)

B.1 Verify Disk Layout

sudo lsblk

Example:

vda
├─vda1   /        ← root filesystem (non‑LVM)
├─vda14
├─vda15  /boot/efi
└─vda16  /boot

B.2 Grow the Root Partition

Replace 1 with your actual partition number.

sudo growpart /dev/vda 1

B.3 Resize the Filesystem

For ext4 (Ubuntu default):

sudo resize2fs /dev/vda1

For XFS:

sudo xfs_growfs /

B.4 Verify the New Size

df -h

✅ Notes