docs: def add_mdisks(self, userid, disk_list, start_vdev=None):
          """Add disks for the userid
  
          :disks: A list dictionary to describe disk info, for example:
                  disk: [{'size': '1g',
                         'format': 'ext3',
                         'disk_pool': 'ECKD:eckdpool1'}]
  
          """
  
          for idx, disk in enumerate(disk_list):
              if 'vdev' in disk:
                  # this means user want to create their own device number
                  vdev = disk['vdev']
              else:
                  vdev = self.generate_disk_vdev(start_vdev=start_vdev,
                                                 offset=idx)
  
              self._add_mdisk(userid, disk, vdev)
              disk['vdev'] = vdev
  
              if disk.get('disk_pool') is None:
                  disk['disk_pool'] = CONF.zvm.disk_pool
  
              sizeUpper = disk.get('size').strip().upper()
              sizeUnit = sizeUpper[-1]
              if sizeUnit != 'G' and sizeUnit != 'M':
                  sizeValue = sizeUpper
                  disk_pool = disk.get('disk_pool')
                  [diskpool_type, diskpool_name] = disk_pool.split(':')
                  if (diskpool_type.upper() == 'ECKD'):
                      # Convert the cylinders to bytes
                      convert = 737280
                  else:
                      # Convert the blocks to bytes
                      convert = 512
                  byteSize = float(float(int(sizeValue) * convert / 1024) / 1024)
                  unit = "M"
                  if (byteSize > 1024):
                      byteSize = float(byteSize / 1024)
                      unit = "G"
                  byteSize = "%.1f" % byteSize
                  disk['size'] = byteSize + unit
  
          return disk_list