text: The hardware compatible with V8.2.1 supports 8 Gbps and 16 Gbps FC fabric, depending on 
  the hardware platform and on the switch to which the Storwize V7000 is connected. In an 
  environment where you have a fabric with multiple-speed switches, the preferred practice is to 
  connect the Storwize V7000 and back-end storage systems to the switch operating at the 
  highest speed. 
  
  You can use the**lsfabric**command to generate a report that displays the connectivity 
  between nodes and other controllers and hosts. This report is helpful for diagnosing SAN 
  problems. 
  
  Storwize V7000 control enclosure contains a pair of nodes (I/O Groups). Odd number of 
  nodes in a cluster is a valid configuration only if a node fails or is removed from the 
  configuration. In such case, the remaining node operates in a degraded mode. 
  
  For clustered systems avoid, if possible, communication between nodes that route across 
  ISLs. Connect all nodes to the same Fibre Channel or FCF switches. 
  
  Direct connection of the system Fibre Channel ports without the use of a Fibre Channel 
  switch is supported. Such direct connections between the system nodes might be useful in 
  small configurations where there is no Fibre Channel switch. It can also be used to connect 
  nodes in the same I/O group to provide a dedicated connection for mirroring the fast write 
  cache data. 