text: **2.5.7 HyperSwap**
  
  IBM HyperSwap function is a high availability feature that provides dual-site, active-active 
  access to a volume. Active-active volumes have a copy in one site and a copy at another site. 
  Data that is written to the volume is automatically sent to both copies so that either site can 
  provide access to the volume if the other site becomes unavailable. Active-active 
  relationships are made between the copies at each site. These relationships automatically 
  run and switch direction according to which copy or copies are online and up to date. 
  
  Relationships can be grouped into consistency groups as with Metro Mirror and Global Mirror 
  relationships. The consistency groups fail over consistently as a group based on the state of 
  all copies in the group. An image that can be used if a disaster occurs is maintained at each 
  site. When the system topology is set to HyperSwap, each IBM Storwize V7000 controller and 
  hostmap object in the system configuration must have a site attribute set to 1 or 2. 
  
  This site must be the same site as the site of the controllers that provide the managed disks to 
  that I/O group. When managed disks are added to storage pools, their site attributes must 
  match. This requirement ensures that each copy in the active-active relationship is fully 
  independent and is at a distinct site. 