On Mon, Apr 22, 2013 at 10:59:25AM +0100, Gary Lloyd wrote: Please email libvirt-users(a)redhat.com for questions about libvirt in the future. This is a question about libvirt domain XML. The documentation is here: http://libvirt.org/formatdomain.html#elementsDisks The attribute is called "error_policy". The documentation says: The optional error_policy attribute controls how the hypervisor will behave on a disk read or write error, possible values are "stop", "report", "ignore", and "enospace".Since 0.8.0, "report" since 0.9.7 The default setting of error_policy is "report". There is also an optional rerror_policy that controls behavior for read errors only. Since 0.9.7. If no rerror_policy is given, error_policy is used for both read and write errors. If rerror_policy is given, it overrides the error_policy for read errors. Also note that "enospace" is not a valid policy for read errors, so if error_policy is set to "enospace" and no rerror_policy is given, the read error policy will be left at its default, which is "report". Stefan