text: **Note:**With volume mirroring, the system creates two copies (Copy0 and Copy1) of a 
  volume. Typically, Copy0 is located in the migration pool, and Copy1 is created in the 
  target pool of the migration. When the host generates a write I/O on the volume, data is 
  written at the same time on both copies. Read I/Os are performed on the preferred 
  copy. 
  
  In the background, a mirror synchronization of the two copies is performed and runs 
  until the two copies are synchronized. The speed of this background synchronization 
  can be changed in the volume properties. 