Tutorial · · 4 min read

Increase Disk Space on Ubuntu Guest VM — No GUI or GParted

Server hardware close-up

Introduction

I'm writing this article mostly for my future self since I already did this kind of expansion twice before. Most online tutorials focus on Ubuntu VMs with graphical interfaces, but I prefer headless Ubuntu Server installations for better performance — no GUI overhead.

Setup:

  • Host OS: Windows 10 Pro
  • Virtualization: VirtualBox
  • Guest OS: Ubuntu Server 20.04 LTS
  • Standard installation without drive encryption

Prerequisites

  • Access to your virtualization software
  • Sudo privileges on the guest VM
  • Cfdisk utility (typically pre-installed on Ubuntu LTS)

Quick Reference (TL;DR)

Sequentially increase the following components:

  1. VDI size via Virtual Media Manager
  2. Physical Volume using cfdisk and pvresize
  3. Volume Group (optional) using vgextend
  4. Logical Volume using lvresize
  5. Filesystem using resize2fs

Step 1: Increase VDI Size

In VirtualBox, open File → Virtual Media Manager. Select your VM's virtual disk image and use the slider or input field to expand it to the desired size.

Step 2: Increase Physical Volume

Using cfdisk

Launch cfdisk which will automatically detect the expanded VDI:

sudo cfdisk

The utility presents straightforward operations: select the partition you want to resize, choose Resize, confirm the new size, then select Write to save changes to disk.

Using pvresize

After exiting cfdisk, expand the physical volume:

sudo pvresize /dev/sda3

Replace /dev/sda3 with your corresponding physical volume.

Step 3: Increase Volume Group (Optional)

This step is only needed when adding a new physical volume rather than resizing an existing one. If you're resizing an existing partition, you can skip this step.

Step 4: Increase Logical Volume

First, verify the physical and logical volume sizes:

sudo fdisk -l

Then allocate all available free space to your logical volume:

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

Replace the path with your actual logical volume path.

Step 5: Increase Filesystem

Finally, make the space available to the operating system:

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

You can verify the expansion was successful with:

df -h

References