text: **7.1.4 Managed mode and image mode volumes**
  
  Volumes are configured within IBM Spectrum Virtualize by allocating a set of extents off one 
  or more managed mode MDisks in the storage pool. Extents are the smallest allocation unit at 
  the time of volume creation, so each MDisk extent maps to exactly one volume extent. 
  
  **Note:**An MDisk extent maps to exactly one volume extent. For volumes with two copies, 
  one volume extent maps to two MDisk extents (one for each volume copy). 
  
  Figure 7-3 shows this mapping. It also shows a volume that consists of several extents that 
  are shown as V0 - V7. Each of these extents is mapped to an extent on one of the MDisks: 
  A, B, or C. The mapping table stores the details of this indirection. 