Increase Diskspace in Proxmox and Make All the Available Free Space Usable in a Ubuntu Linux VM

Steps

Shutdown VM

1. In Proxmox, select the VM you would like to add disk space to.
2. Select the Hardware tab.
3. Click on the Hard Disk you want to resize.
4. Click Disk Action (above all the hardware details) then Resize.
5. Enter the amount of space you would like to increase the disk by. (This is additive. If your disk is currently 32GB and you want it to be 64GB, you would need to add 32GB.)
6. Start the VM.

Terminal to VM and Login

1. Drop to Sudo:

   sudo su

Check for Free Space

1. Run:

   df -h

   Nothing should have changed at this point.

Resize the Disk

1. Run:

   cfdisk

2. At the bottom of the list, you should see ">> Free space". This will be equal to the amount you added to your disk above.
3. Select the partition you would like to resize (something like /dev/sda3 you will need this in the next step).
4. Select RESIZE and hit ENTER.
5. The new size will use the entire amount of free disk space by default, hit ENTER.
6. Click WRITE, then type 'yes', and press ENTER to commit the change.
7. You should no longer see the ">> Free space" in the list.
8. Press 'q' or select Quit.

Extend the Partition

1. Run:

   pvresize {Volume}

   {Volume} will be the device you resized in cfdisk (something like /dev/sda3).

Check Volume Group for Free Space

1. Run:

   vgdisplay

Get the LV Path

1. Run:

   lvdisplay

2. Copy the LV Path.

Extend the Volume

1. Run:

   lvextend -l +100%FREE {LVPath}

   {LVPath} will be something like /dev/ubuntu-vg/ubuntu-lv.

Confirm Changes

1. Run:

   lvdisplay

Get Root File System Path

1. Run:

   df -h

2. Copy the /dev/mapper full path.

Resize Root File System

1. Run:

   resize2fs {RootFSPath}

   {RootFSPath} was copied in the previous step and should be something like /dev/mapper/ubuntu--vg-ubuntu--lv.

Confirm Changes

1. Run:

   df -h

Optional: Reboot the Newly Resized VM