@ConfigSync()
  def SetDiskLogicalID(self, disk_uuid, logical_id):
    disk = self._UnlockedGetDiskInfo(disk_uuid)
    if disk is None:
      raise errors.ConfigurationError("Unknown disk UUID '%s'" % disk_uuid)

    if len(disk.logical_id) != len(logical_id):
      raise errors.ProgrammerError("Logical ID format mismatch\n"
                                   "Existing logical ID: %s\n"
                                   "New logical ID: %s", disk.logical_id,
                                   logical_id)

    disk.logical_id = logical_id
Sets the logical_id of an existing disk
dataset/ETHPy150Open ganeti/ganeti/lib/config/__init__.py/ConfigWriter.SetDiskLogicalID