Note to take :
lvdisplay => note PV Path and note VG Name to extend (for LV Path/Name choosed), for example "system".
vgdisplay => confirm format (lvm2)

After adding disk or resize VDI :
fdisk -l
fdisk /dev/sda => add new primary or logical volume, for example "sda3"
pvscan or pvdisplay or pvs => does NOT show new partition
pvcreate /dev/sda3
pvscan or pvdisplay or pvs => show new partition
vgextend system /dev/sda3 (where system is VG Name)
lvextend -l +100%FREE /dev/system/root (where /dev/system/root is the PV Path noted before)
resize2fs /dev/system/root

It's done.
Confirm with df -h command