GLYPH<SM590000> Warning threshold:  Whether a warning message should be sent, and at what percentage  of filled virtual capacity. Defaults to  Enabled , with a warning threshold set at 80%. GLYPH<SM590000> Thin-Provisioned Grain Size:  Allows you to define the grain size for the thin-provisioned  volume. Defaults to 256 KiB. GLYPH<SM590000> If you are not  going to use the thin-provisioned volume as a FlashCopy source or  target volume, use 256 KiB to maximize performance.  GLYPH<SM590000> 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. GLYPH<SM590000> If you plan to use EasyTier with thin-provisioned volumes, then review the IBM  Support article  Performance Problem When Using EasyTier With Thin  Provisioned Volumes  at: Important:  If you do not use the  autoexpand  feature, the volume goes off line 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 these points: http://www.ibm.com/support/docview.wss?uid=ssg1S1003982 If you choose to create a compressed volume, a Compressed pane is displayed, as shown in  Figure 7-21. This pane gives the following options: You cannot specify grain size for a compressed volume. GLYPH<SM590000> Real capacity:  Real capacity of the volume, specified either as percentage of the virtual  capacity, or in bytes. GLYPH<SM590000> Automatically expand:  Whether to automatically expand the real capacity of the volume  if needed. Defaults to  Enabled . GLYPH<SM590000> Warning threshold:  Whether a warning message should be sent, and at what percentage  of filled virtual capacity. Defaults to  Enabled , with a warning threshold set at 80%. Note:  Before you create the first compressed volume copy on a system, consider the  compression guidelines in Chapter 10, “Advanced features for storage efficiency” on  page 427. Figure 7-21 Custom volume creation – Compressed pane Compressed pane 290  Implementing the IBM System Storage SAN Volume Controller with IBM Spectrum Virtualize V8.2.1