text: Figure 10-10 Thin VDisk parameters 
  
  In a DRP pool, thin provisioned volume fine-tuning is not required. Real capacity (rsize) value 
  is ignored, and Grain Size is fixed to 8 KB. 
  
  When a thin-provisioned volume is created in a standard pool, Real capacity (rsize) defines 
  both initial volume real capacity and an amount of contingency capacity, which is used by 
  autoexpand. 
  
  Write I/Os to the grains of the thin volume in a standard pool (that were not previously written 
  to) cause grains of the real capacity to be used to store metadata and user data. Write I/Os to 
  the grains (that were previously written to) update the grain where data was written. The grain 
  is defined when the volume is created, and can be 32 KiB, 64 KiB, 128 KiB, or 256 KiB. 
  
  Smaller granularities can save more space, but they have larger metadata directories. When 
  you use thin-provisioning with FlashCopy, specify the same grain size for the thin-provisioned 
  volume and FlashCopy. 
  
  **Host considerations**
  Do not use defragmentation applications on thin-provisioned volumes. The defragmentation 
  process can write data to different areas of a volume, which can cause a thin-provisioned 
  volume to grow up to its virtual size. 