🖥️ Ubuntu Virtual Machine Disk Expansion Reference Guide¶
This guide provides documentation for increasing the disk size of an Ubuntu virtual machine hosted in a Proxmox Virtual Environment. It covers both the virtual disk resize in Proxmox and the steps inside Ubuntu to use the additional space.
⚡ Quick Reference Table¶
| Step | Command | Purpose | Expected Output / Notes |
|---|---|---|---|
| 1. Verify Disk Layout | sudo lsblk |
Check current disk and partition sizes | Shows all disks, partitions, and LVMs. SIZE should reflect new disk size. |
| 2. Grow Partition | sudo growpart /dev/sda 3 |
Expand partition 3 to use added space |
CHANGED: partition=3 ... confirms the partition was resized |
| 3. Resize Physical Volume | sudo pvresize /dev/sda3 |
Resize LVM physical volume to use new partition | Physical volume "/dev/sda3" changed |
| 4. Extend Logical Volume | sudo lvextend -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv |
Expand logical volume to consume all free space | Size of logical volume ... changed ... successfully resized |
| 5. Resize File System | sudo resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv |
Apply changes to filesystem | The filesystem ... is now ... blocks long |
| 6. Verify New Size | df -h |
Confirm filesystem uses expanded disk | Output shows increased size for / filesystem |
1️⃣ Increase the Virtual Machine Disk in Proxmox¶
To increase the VM disk size:
| Step | Action | Notes |
|---|---|---|
| 1 | Shut down the virtual machine | ⚡ Ensure the VM is powered off before modifying disk settings |
| 2 | Open the VM’s Hardware settings in Proxmox | Navigate to the VM → Hardware tab |
| 3 | Select the hard disk, click Disk Action → Resize | Enter the size increment in GiB |
| 4 | Click Resize Disk | Proxmox will adjust the virtual disk size |
⚡ Tip: Do not boot the VM until the disk resize operation is complete.
2️⃣ Increase the Disk Partition in Ubuntu¶
After booting the VM, follow these steps to make the extra space available inside Ubuntu.
2.1 Verify the New Disk Size¶
sudo lsblk
✅ Example output:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 15G 0 disk
├─sda1 8:1 0 1M 0 part
├─sda2 8:2 0 1.8G 0 part /boot
└─sda3 8:3 0 13.2G 0 part
└─ubuntu--vg-ubuntu--lv 252:0 0 13.2G 0 lvm /
⚡ The
SIZEcolumn should reflect the new disk size.
2.2 Grow the Partition¶
sudo growpart /dev/sda 3
✅ Example output:
CHANGED: partition=3 start=3674112 old: size=17297408 end=20971519 new: size=27787231 end=31461342
2.3 Resize the Physical Volume¶
sudo pvresize /dev/sda3
✅ Example output:
Physical volume "/dev/sda3" changed
1 physical volume(s) resized or updated / 0 physical volume(s) not resized
2.4 Extend the Logical Volume¶
sudo lvextend -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv
✅ Example output:
Size of logical volume ubuntu-vg/ubuntu-lv changed from <8.25 GiB (2111 extents) to <13.25 GiB (3391 extents).
Logical volume ubuntu-vg/ubuntu-lv successfully resized.
2.5 Resize the File System¶
sudo resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv
✅ Example output:
resize2fs 1.47.0 (5-Feb-2023)
Filesystem at /dev/mapper/ubuntu--vg-ubuntu--lv is mounted on /; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 2
The filesystem on /dev/mapper/ubuntu--vg-ubuntu--lv is now 3472384 (4k) blocks long.
2.6 Verify the New Size¶
df -h
✅ Example output:
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/ubuntu--vg-ubuntu--lv 13G 6.9G 5.5G 56% /
/dev/sda2 1.7G 191M 1.4G 12% /boot
✅ Notes¶
- Always backup important data before resizing disks or partitions.
- Ensure Proxmox snapshots are available in case rollback is needed.
- Commands assume LVM-managed partitions. Standard partitions may require different commands.
- Step order matters: grow partition → resize PV → extend LV → resize FS.
This combined document gives you both a Quick Reference Table for fast lookup and a detailed step-by-step guide for understanding each command, expected output, and best practices—consistent with your Home Lab documentation style.