when starting a vm of a pool  fails.    in the process of hooks, i modify guestvm hostname, and modify the path of backing file of chain.  do nothing else. 
i can munually define a xml(after hooks), and start it without error.
 
 
env:
libvirt-0.10.2-18.el6_4.5.x86_64
2.6.32-358.6.2.el6.x86_64
centos6.4
 
 
1.where does this error message come from ?
Storage.StorageDomain WARNING Could not find mapping for lv d028d521-d4a9-4dd7-a0fe-3e9b60e7c4e4/cae1bb2d-0529-4287-95a3-13dcb14f082f
 
2.
Thread-6291::ERROR::2013-09-18 12:44:21,205::vm::683::vm.Vm::(_startUnderlyingVm) vmId=`24f7e975-9aa5-4a14-b0f0-590add14c8b5`::The vm start process failed
Traceback (most recent call last):
  File "/usr/share/vdsm/vm.py", line 645, in _startUnderlyingVm
    self._run()
  File "/usr/share/vdsm/libvirtvm.py", line 1529, in _run
    self._connection.createXML(domxml, flags),
  File "/usr/lib64/python2.6/site-packages/vdsm/libvirtconnection.py", line 83, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 2645, in createXML
    if ret is None:raise libvirtError('virDomainCreateXML() failed', conn=self)
libvirtError: internal error Process exited while reading console log output: char device redirected to /dev/pts/4
qemu-kvm: -drive file=/rhev/data-center/7828f2ae-955e-4e4b-a4bb-43807629dc52/d028d521-d4a9-4dd7-a0fe-3e9b60e7c4e4/images/ac025dc1-4e25-4b71-8c56-88dcb61b9f09/cae1bb2d-0529-4287-95a3-13dcb14f082f,if=none,id=drive-ide0-0-0,format=qcow2,serial=ac025dc1-4e25-4b71-8c56-88dcb61b9f09,cache=none,werror=stop,rerror=stop,aio=native: could not open disk image /rhev/data-center/7828f2ae-955e-4e4b-a4bb-43807629dc52/d028d521-d4a9-4dd7-a0fe-3e9b60e7c4e4/images/ac025dc1-4e25-4b71-8c56-88dcb61b9f09/cae1bb2d-0529-4287-95a3-13dcb14f082f: Operation not permitted