text: Figure 2-15 Global Mirror with change volumes 
  
  In asynchronous remote copy, the application acknowledges that the write is complete before 
  the write is committed at the secondary volume. Therefore, on a failover, certain updates 
  (data) might be missing at the secondary volume. The application must have an external 
  mechanism for recovering the missing updates, if possible. This mechanism can involve user 
  intervention. Recovery on the secondary site involves starting the application on this recent 
  backup, and then rolling forward or backward to the most recent commit point. 
  
  **2.5.26 FlashCopy and Transparent Cloud Tiering**
  
  FlashCopy and Cloud Backup are used to make a copy of a source volume on a target 
  volume. After the copy operation starts, the original content of the target volume is lost. The 
  target volume has the contents of the source volume as they existed at a single point in time. 
  Although the copy operation takes time, the resulting data at the target appears as though the 
  copy was made instantaneously. 
  
  **FlashCopy**
  FlashCopy is sometimes described as an instance of a time-zero (T0) copy or a point-in-time 
  (PiT) copy technology. 
  
  FlashCopy can be performed on multiple source and target volumes. FlashCopy permits the 
  management operations to be coordinated so that a common single point in time is chosen 
  for copying target volumes from their respective source volumes. 