Quick Note: This is only suitable for specific usecases! This can especially be useful in single-disk setups, where many VMs are going to be created.

With the default Proxmox setup, "local" stores the ISO images and container templates, and 'local-lvm' stores the installed VMs and containers themselves. Apparently, deleting "local-lvm" in order to resize "local" removes the ability to take snapshots of each VM and container.

Step 1: Navigate to "Datacenter ---> Storage". Select "local-lvm" and click on "Remove".

Step 2: Enter the following commands in this particular order:

  # lvremove /dev/pve/data
    

  # lvresize -l +100%FREE /dev/pve/root
    

  # resize2fs /dev/mapper/pve-root