'Create a snapVx of a volume.
:param array: the array serial number
:param source_device_id: source volume device id
:param snap_name: the snapshot name
:param extra_specs: the extra specifications'

def create_volume_snapvx(self, array, source_device_id, snap_name, extra_specs):

    start_time = time.time()
    LOG.debug('Create    Snap    Vx    snapshot    of:    %(source)s.', {'source': source_device_id})
    self.rest.create_volume_snap(array, snap_name, source_device_id, extra_specs)
    LOG.debug('Create    volume    snapVx    took:    %(delta)s    H:MM:SS.', {'delta': self.utils.get_time_delta(start_time, time.time())})
