code: def mount(self, volume):
          
  
          volume._find_loopback()
  
          raid_status = None
          try:
              # use mdadm to mount the loopback to a md device
              # incremental and run as soon as available
              output = _util.check_output_(['mdadm', '-IR', volume.loopback], stderr=subprocess.STDOUT)
  
              match = re.findall(r"attached to ([^ ,]+)", output)
              if match:
                  volume._paths['md'] = os.path.realpath(match[0])
                  if 'which is already active' in output:
                      logger.info("RAID is already active in other volume, using %s", volume._paths['md'])
                      raid_status = 'active'
                  elif 'not enough to start' in output:
                      volume._paths['md'] = volume._paths['md'].replace("/dev/md/", "/dev/md")
                      logger.info("RAID volume added, but not enough to start %s", volume._paths['md'])
                      raid_status = 'waiting'
                  else:
                      logger.info("RAID started at {0}".format(volume._paths['md']))
                      raid_status = 'active'
          except Exception as e:
              logger.exception("Failed mounting RAID.")
              volume._free_loopback()
              raise SubsystemError(e)
  
          # search for the RAID volume
          for v in volume.disk.parser.get_volumes():
              if v._paths.get("md") == volume._paths['md'] and v.volumes:
                  logger.debug("Adding existing volume %s to volume %s", v.volumes[0], volume)
                  v.volumes[0].info['raid_status'] = raid_status
                  volume.volumes.volumes.append(v.volumes[0])
                  return v.volumes[0]
          else:
              logger.debug("Creating RAID volume for %s", self)
              container = volume.volumes._make_single_subvolume(flag='alloc', offset=0, size=volume.size)
              container.info['fsdescription'] = 'RAID Volume'
              container.info['raid_status'] = raid_status
              return container
docs: Add the volume to a RAID system. The RAID array is activated as soon as the array can be activated.
  
          :raises NoLoopbackAvailableError: if no loopback device was found