text: This pane includes the following options: 
  
  (cid:2) Real capacity: Real capacity of the volume, which is specified as percentage of the virtual 
  capacity or in bytes. 
  
  (cid:2) Automatically expand: Whether to automatically expand the real capacity of the volume if 
  needed; defaults to Enabled. 
  
  (cid:2) Warning threshold: Whether a warning message is sent and at what percentage of filled 
  virtual capacity; defaults to Enabled, with a warning threshold set at 80%. 
  
  (cid:2) Thin-Provisioned Grain Size: Allows you to define the grain size for the thin-provisioned 
  volume; defaults to 256 KiB. 
  
  **Important:**If you do not use the**autoexpand**feature, the volume goes offline if it 
  receives a write request after all real capacity is allocated. 
  
  The default grain size is 256 KiB. The optimum choice of grain size is dependent upon 
  volume use type. Consider the following points: 
  
  (cid:2) If you are*not*going to use the thin-provisioned volume as a FlashCopy source or 
  target volume, use 256 KiB to maximize performance. 
  
  (cid:2) If you*are*going to use the thin-provisioned volume as a FlashCopy source or target 
  volume, specify the same grain size for the volume and for the FlashCopy function. 
  
  (cid:2) If you plan to use EasyTier with thin-provisioned volumes, see the IBM Support 
  article Performance Problem When Using EasyTier With Thin Provisioned Volumes. 