LVM over NFS

Hi,
I can't have access to an iSCSI SAN (just NFS). So, would it be safe to :
- Create a huge file in the nfs partition (~ 500Go)
- Create a device from this file (loopback)
- Make a LVM volume using this loopback device, and use it form VMs and CTs

My cluster is made of 3 nodes.
Thanks in advance !