Resize/Grow LVM-volume

Firstly show all available LVMs:

lvdisplay

The output might look like this:

  --- Logical volume ---
  LV Path                /dev/pve/swap
  LV Name                swap
  VG Name                pve
  LV UUID                U1Mc2n-WRuL-P8Li-yIb6-AXN8-ueDd-oYfwOu
  LV Write Access        read/write
  LV Creation host, time proxmox, 2023-08-19 09:49:14 +0200
  LV Status              available
  # open                 2
  LV Size                8.00 GiB
  Current LE             2048
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           252:0
 
  --- Logical volume ---
  LV Path                /dev/pve/root
  LV Name                root
  VG Name                pve
  LV UUID                IPbLTf-3SnK-ECmv-ABqX-Wet7-c66F-UfBYT3
  LV Write Access        read/write
  LV Creation host, time proxmox, 2023-08-19 09:49:14 +0200
  LV Status              available
  # open                 1
  LV Size                96.00 GiB
  Current LE             24576
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           252:1

Then use lsblk to view free space:

NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
loop0          7:0    0     8G  0 loop 
loop1          7:1    0     8G  0 loop 
loop2          7:2    0     8G  0 loop 
loop3          7:3    0    16G  0 loop 
nvme0n1      259:0    0 476.9G  0 disk 
├─nvme0n1p1  259:1    0  1007K  0 part 
├─nvme0n1p2  259:2    0     1G  0 part /boot/efi
└─nvme0n1p3  259:3    0 475.9G  0 part 
  ├─pve-swap 252:0    0     8G  0 lvm  [SWAP]
  └─pve-root 252:1    0    96G  0 lvm  /

Now extend the volume with lvextend, 200G is the new size of the volume:

lvextend -L 200G /dev/pve/root

Finally resize the filesytem:

resize2fs /dev/pve/root