text: The source and target volumes must be the same size. The minimum granularity that IBM 
  Spectrum Virtualize supports for FlashCopy is an entire volume. It is not possible to use 
  FlashCopy to copy only part of a volume. 
  
  **Important:**As with any T0 copy technology, you are bound by operating system and 
  application requirements for interdependent data and the restriction to an entire volume. 
  
  The source and target volumes must belong to the same IBM SAN Volume Controller system, 
  but they do not have to be in the same I/O Group or storage pool. 
  
  Volumes that are members of a FlashCopy mapping cannot have their size increased or 
  decreased while they are members of the FlashCopy mapping. 
  
  All FlashCopy operations occur on FlashCopy mappings. FlashCopy does not alter the 
  volumes. However, multiple operations can occur at the same time on multiple FlashCopy 
  mappings, thanks to the use of Consistency Groups. 
  
  **11.1.4 Consistency Groups**
  
  To overcome the issue of dependent writes across volumes and to create a consistent image 
  of the client data, a FlashCopy operation must be performed on multiple volumes as an 
  atomic operation. To accomplish this method, the IBM Spectrum Virtualize supports the 
  concept of*Consistency Groups*. 