[one-users] Multiple VM instances using one persistent image

[Robert Maier]

Hi,

I set up ONE on a small cluster and got in trouble as I tried to use one
persistent (live-cd) image by several VMs. The image is marked to be of
type CDROM and is the VM's only disk. As the first VM is created, it
boots properly and runs fine. When I try to create another instance of
the same VM (template) I get an error printed on the terminal:

Error: [VirtualMachineAllocate] Error trying to CREATE VM Could not get
disk image for VM.

This problem does not occur, if I set the image to public instead of
persistent, i.e. the image is copied to VM_DIR instead of a symbolic
link is being created.
Why is it not possible to use one persistent image by multiple VMs? I
thought persistent means (in some way) read-only. Thus, there should be
no need to lock the image when it is used by a VM.

Thanks in advance.
Robert