text: The quota of background copy (configured on the intercluster link) is divided evenly between 
  all nodes that are performing background copy for one of the eligible relationships. This 
  allocation is made irrespective of the number of disks for which the node is responsible. Each 
  node in turn divides its allocation evenly between the multiple relationships that are 
  performing a background copy. 
  
  The default value of the background copy is 25MBps per volume. 
  
  **Important:**The background copy value is a system-wide parameter that can be changed 
  dynamically, but only on a per-system basis and not on a per-relationship basis. Therefore, 
  the copy rate of all relationships changes when this value is increased or decreased. In 
  systems with many remote copy relationships, increasing this value might affect overall 
  system or intercluster link performance. The background copy rate can be changed to 
  1 - 1000 MBps. 