Proxmox Web UI에서 늘리고자하는 VM을 선택
Hardware 탭 > Hard Disk > Disk Action > Resize
sudo fdisk -l
sudo growpart /dev/sda 3 <= 1번에서 확인한 Device의 넘버
sudo pvresize /dev/sda3
sudo lvdisplay
sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
resize2fs /dev/ubuntu-vg/ubuntu-lv
sudo fdisk -l
출처: https://forum.proxmox.com/threads/resize-ubuntu-vm-disk.117810