text: **11.11 Troubleshooting remote copy**
  
  Remote copy (Metro Mirror and Global Mirror) has two primary error codes that are displayed: 
  
  (cid:2) A 1920 error can be considered as a voluntary stop of a relationship by the system when it 
  evaluates the replication will cause errors on the hosts. A 1920 is a congestion error. This 
  error means that the source, the link between the source and target, or the target cannot 
  keep up with the requested copy rate. The system then triggers a 1920 error to prevent 
  replication from having undesired effects on hosts. 
  
  (cid:2) A 1720 error is a heartbeat or system partnership communication error. This error often is 
  more serious because failing communication between your system partners involves 
  extended diagnostic time. 
  
  **11.11.1 1920 error**
  
  A 1920 error is deliberately generated by the system and should be considered as a control 
  mechanism. It occurs after 985003 (“Unable to find path to disk in the remote cluster (system) 
  within the time-out period”) or 985004 (“Maximum replication delay has been exceeded”) 
  events. 
  
  It can have several triggers, including the following probable causes: 
  
  (cid:2) Primary system or SAN fabric problem (10%) 
  (cid:2) Primary system or SAN fabric configuration (10%) 
  (cid:2) Secondary system or SAN fabric problem (15%) 
  (cid:2) Secondary system or SAN fabric configuration (25%) 
  (cid:2) Intercluster link problem (15%) 
  (cid:2) Intercluster link configuration (25%) 