text: **11.6.11 Asynchronous remote copy**
  
  Global Mirror is an asynchronous remote copy technique. In asynchronous remote copy, the 
  write operations are completed on the primary site and the write acknowledgment is sent to 
  the host before it is received at the secondary site. An update of this write operation is sent to 
  the secondary site at a later stage, which provides the capability to perform remote copy over 
  distances that exceed the limitations of synchronous remote copy. 
  
  The Global Mirror function provides the same function as Metro Mirror remote copy, but over 
  long-distance links with higher latency without requiring the hosts to wait for the full round-trip 
  delay of the long-distance link. 
  
  Figure 11-89 shows that a write operation to the master volume is acknowledged back to the 
  host that is issuing the write before the write operation is mirrored to the cache for the 
  auxiliary volume. 