Growing Ubuntu LVM root filesystem inside a VM under Proxmox PVE

I wanted to grow the root filesystem of an Ubuntu 18.04 VM hosted in Proxmox PVE from 500GB to 2TB.

The VM is well backed up using Proxmox Backup Server and I have been through similar efforts with other VMs in other environments so I felt confident enough to proceed. 

I started by shutting down the VM and using the PVE GUI  (Hardware > Hard Disk > Disk Action > Resize) and specifying 2000 in the GB box. Then I started the VM, confirmed the change and shutdown again to take a snapshot before proceeding.

After booting the VM again I started to work through what I thought would be a relatively straightforward process of growing the partition, growing the physical volume, growing the logical volume, and then growing the filesystem.

It wasn't working as well as I expected. Searching online showed how to add a new partition of type `8e` (Linux LVM) to consume the free space, then creating a physical volume on it, then adding it to the volume group, then extending the root volume.

I thought this was a bit messy and thought there must be a way to just grow the existing partition without having to create a new one. Running `growpart /dev/sda 5` seemed to suggest that it was able to add a bunch of space to the partition but none of the pv, vg, and lv display, extending, or resizing commands seemed to suggest that the free space was available or that growth was possible.

In the end I perhaps jumped the gun by removing the swap LV thinking that it was blocking the growth of the root LV. Then I realized that the /dev/sda5 partition hosting the VG was an extended partition and that /dev/sda2 (the primary partition assigned to hold extended partitions) might need to be grown before /dev/sda5.

So what I ended up with was more or less:

 

swapoff -a

lvremove hostname-vg/swap_1 

growpart /dev/sda 2 

growpart /dev/sda 5

pvresize /dev/sda5 

lvextend hostname-vg/root /dev/sda5

resize2fs /dev/hostname-vg/root

 

But I'm not sure that I actually needed to remove the swap and was maybe just missing the `growpart /dev/sda 2` before the `growpart /dev/sda 5` and the rest to make it work. The next time I need to do this... try without removing swap first.