text: Figure 2-14 Image mode volume 
  
  Some virtualization functions are not available for image mode volumes, so it is often useful to 
  migrate the volume into a new storage pool. After it is migrated, the MDisk becomes a 
  managed MDisk. 
  
  If you add an MDisk that contains data to a storage pool, any data on the MDisk is lost. 
  Ensure that you create image mode volumes from MDisks that contain data before adding 
  MDisks to the storage pools. 
  
  **2.5.17 Easy Tier**
  
  IBM Easy Tier is a performance optimization function that automatically migrates or moves 
  the extents of a volume across two or more tiers. Easy Tier monitors the host I/O activity and 
  latency on the extent of all volumes with the Easy Tier function turned on, in a multitiered 
  storage pool, over a 24-hour period. 
  
  After this period, the IBM Easy Tier creates an extent migration plan that is based on this 
  activity, and then dynamically moves high activity (or*hot*) extents to a higher disk tier within 
  the storage pool. It also moves extent activity that dropped off (or*cooled*) from the high-tiered 
  MDisk back to a lower-tiered MDisk. 