[Users] image ownership

Greetings all, I've set up a new oVirt installation and it's behaving strangely with regard to virtual machine image files on the NFS storage. Whenever I shut down a machine it's changing the owner of the image to root:root (0:0) instead of vdsm:kvm (36:36). After that it can't start or do anything with that image again until I manually change the ownership back. Everything works fine again until I shut the machine down. I assume this is some mistake I've made in installation. I did not have this problem in the test environment, but I'm stumped as to what went wrong. -Jacob