text: To avoid any significant impact on performance because of multiple targets, FlashCopy 
  creates dependencies between the targets. Dependencies can be considered as “hidden” 
  FlashCopy mappings that are not visible to and cannot be managed by the user. A 
  dependency is created between the most recent target and the previous one (in order of start 
  time). Figure 11-13 shows an example of a source volume with three targets. 
  
  When the three targets are started, Target T0 was started first and considered the “oldest.” 
  Target T1 was started next and is considered “next oldest,” and finally Target T2 was started 
  last and considered the “most recent” or “newest.” The “next oldest” target for T2 is T1. The 
  “next oldest” target for T1 is T0. T1 is newer than T2, and T0 is newer than T1. 