text: **Background copy bandwidth effect on foreground I/O latency**
  The combination of the Link Bandwidth value and the Background Copy Rate percentage is 
  referred to as the*Background Copy bandwidth*. It must be at least 8 Mbps. For example, if the 
  Link Bandwidth is set to 10000 and the Background Copy Rate is set to 20, then the resulting 
  Background Copy bandwidth that is used for background operations is 200 Mbps. 
  
  The background copy bandwidth determines the rate at which the background copy is 
  attempted for MM/GM. The background copy bandwidth can affect foreground I/O latency in 
  one of the following ways: 
  
  (cid:2) The following results can occur if the background copy bandwidth is set too high compared 
  to the MM/GM intercluster link capacity: 
  
  – The background copy I/Os can back up on the MM/GM intercluster link. 
  – There is a delay in the synchronous auxiliary writes of foreground I/Os. 
  – The foreground I/O latency increases as perceived by applications. 
  
  (cid:2) If the background copy bandwidth is set too high for the storage at the primary site, 
  background copy read I/Os overload the primary storage and delay foreground I/Os. 
  
  (cid:2) If the background copy bandwidth is set too high for the storage at the secondary site, 
  background copy writes at the secondary site overload the auxiliary storage, and again 
  delay the synchronous secondary writes of foreground I/Os. 