text: **Note:**You can use more than four fabric ports per node to improve peak load I/O 
  performance. However, if a node receives more than 16 logins from another node, it 
  causes node error 860. To avoid this error, you must use zoning, port masking, or 
  combination of the two. For more information, see 3.6.7, “Port designation 
  recommendations” on page 58, 3.6.8, “Port masking” on page 59, and the IBM Storwize 
  V7000 documentation. 