WARNING: PV /dev/sda3 in VG ubuntu-vg is using an old PV header, modify the VG to update

Solution 1:

'VG' in the warning means volume group. This is applicable to systems using logical volume management. 'PV' stands for physical volume, that is the actual partitions on disk(s). Headers contains information about the volume group's layout which can be used for data recovery.

You can try to resolve this with the tool vgck which checks volume group metadata and can rewrite it to correct problems with the --updatemetadata command. You need to give the name of the volume group mentioned in your warning - in your case it says that the physical volume /dev/sda3 (that's a disk partition device file) which is in volume group ubuntu-vg is using an old header, so probably the metadata needs to be updated. To do that you can use this command:

sudo vgck --updatemetadata ubuntu-vg