'Returns volroot property value from NexentaStor appliance.'

def _get_volroot(self, nms):

    if (not self.nms_cache_volroot):
        return nms.server.get_prop('volroot')
    if (nms not in self._nms2volroot):
        self._nms2volroot[nms] = nms.server.get_prop('volroot')
    return self._nms2volroot[nms]
