text: Figure 11-11 Incremental FlashCopy example 
  
  **11.1.10 Starting FlashCopy mappings and Consistency Groups**
  
  You can perform the actions of preparing, starting, or stopping FlashCopy on a stand-alone 
  mapping or a Consistency Group. 
  
  When using the CLI to perform FlashCopy on volumes, before you start a FlashCopy 
  (regardless of the type and options specified), issue a**prestartfcmap**or 
  **prestartfcconsistgrp**command. These commands put the cache into write-through mode 
  and provides a flushing of the I/O that is bound for your volume. After FlashCopy is started, an 
  effective copy of a source volume to a target volume is created. 
  
  The content of the source volume is presented immediately on the target volume and the 
  original content of the target volume is lost. 
  
  FlashCopy commands can then be issued to the FlashCopy Consistency Group and 
  therefore, simultaneously for all of the FlashCopy mappings that are defined in the 
  Consistency Group. For example, when a FlashCopy start command is issued to the 
  Consistency Group, all of the FlashCopy mappings in the Consistency Group are started at 
  the same time. This simultaneous start results in a point-in-time copy that is consistent across 
  all of the FlashCopy mappings that are contained in the Consistency Group. 