Reduce vdisk LV size
To reduce the size of a virtual disk containing lvm partitioning do the following:
shutdown the vm and add gparted iso to dvd drive
boot into gparted and open terminal
run lvdisplay to see the root lv name and path
sudo lvdisplay
resize the root lv
sudo lvreduce --resizefs -L {size}G /dev/vg_blah/lv_blah
run pvdisplay to see the volume name/number
sudo pvdisplay
resize the pv
sudo pvresize --setphysicalvolumesize {size}G /dev/sdaX
In gparted GUI reduce the partition size as required
shutdown the guest and in the host resize the physical disk
(careful not to chop off the end of the last partition THINK!!!)
lvresize --size {size}G /dev/pve/vm-10X-disk-X
boot back into gparted
(ignore the warning, then fix partition table from terminal)
sudo gparted /dev/sdaX
x (for expert mode)
e (to relocate the backup partition table to end of disk)
w (to write changes to disk exit)
in terminal resize the pv
(think this might be done by gparted already)
pvresize /dev/sdaX
resize the lv to use all available space
lvresize -l +100%FREE /dev/vg_blah/lv_blah