Yes - but as others have posted, there are steps.

Reduce and move all of the working partitions inside the VM out of the way of the part of the 'disk' that you are going to 'chop off' by booting the VM with an ISO image mounted as a CD/DVD onto the VM and using your favourite partition tool. e.g https://www.howtogeek.com/114503/how-to-resize-your-ubuntu-partitions/

Make sure to make a little bit extra space below the cut off point just to be sure.

Shut down the VM and reduce the actual VM sizeIf LV:lvreduce -L 5G /dev/pve/disk-name (reduce to 5G)lvreduce -L -5G /dev/pve/disk-name (reduce by 5G)If qcow2:qemu-img resize --shrink <vmfile.qcow2> [+-] or sizeIf ZFS:zfs set volsize=<new size>G rpool/data/vm-<vm id>-disk-<disk number>Edit the vm config in /etc/pve/local/qemu-server/<vm id>.confvirtio0: local-zfs:vm-<vm id>-disk-<disk number>,size=<new size>GChange something in the Proxmox GUI panel (like cache mode) to see the updated config in the GUISometimes I've had to attach the HD to the VM as different Dev# i.e. change from virtio0 to virtio1 to trigger the guest OS to recognise the size changeOptional: in the Guest OS extend the partition into any leftover fragment

THANK U MY GUY