text: **7.1.8 Fully allocated and thin-provisioned volumes**
  
  For each volume the following parameters describe its capacity: 
  
  (cid:2) The real physical capacity that is allocated to the volume from the storage pool; 
  determines how many MDisk extents are initially allocated to the volume. 
  
  (cid:2) The virtual capacity that is reported to the host and to IBM Spectrum Virtualize 
  components (for example, FlashCopy, cache, and remote copy). 
  
  In a*fully allocated*volume, these two values are the same. In a*thin-provisioned*volume, the 
  real capacity can be as little as a few percent of virtual capacity. The*real capacity*is used to 
  store the user data and in the case of thin-provisioned volumes, metadata of the volume. The 
  real capacity can be specified as an absolute value, or as a percentage of the virtual capacity. 
  
  Thin-provisioned volumes can be used as volumes that are assigned to the host by 
  FlashCopy to implement thin-provisioned FlashCopy targets. When creating a mirrored 
  volume, a thin-provisioned volume can be created as a second volume copy, whether the 
  primary copy is a fully or thin-provisioned volume. 