text: Your change rate needs to include only the condition of the data at the point-in-time that the 
  image was taken, rather than all the updates during the period. The use of this function can 
  provide significant reductions in replication volume. 
  
  Global Mirror with Change Volumes has the following characteristics: 
  
  (cid:2) Larger RPO 
  
  (cid:2) Point-in-time copies 
  
  (cid:2) Asynchronous 
  
  (cid:2) Possible system performance resource requirements because point-in-time copies are 
  created locally 
  
  Figure 11-92 shows a simple Global Mirror relationship without Change Volumes. 