text: When you configure change volumes for use with Global Mirror, two internal FlashCopy 
  mappings are created for each change volume. 
  
  For Metro Mirror, Global Mirror, and HyperSwap active-active relationships, two bitmaps exist. 
  For MM/GM relationships, one is used for the master clustered system and one is used for the 
  auxiliary system because the direction of the relationship can be reversed. For active-active 
  relationships, which are configured automatically when HyperSwap volumes are created, one 
  bitmap is used for the volume copy on each site because the direction of these relationships 
  can be reversed. 
  
  MM/GM relationships do not automatically increase the available bitmap space. You might 
  need to use the**chiogrp**command to manually increase the space in one or both of the 
  master and auxiliary systems. 
  
  You can modify the resource allocation for each I/O group of an IBM SAN Volume Controller 
  system by opening the**Settings**→**System**panel and clicking the**Resources**menu, as 
  shown in Figure 11-154. 