Hello iDigIT,  Adding onto what ChrisPy noted - When the cluster is first created, it is expected that a single link failure would be accrued during the initialization process.  A single instance of link failure should not be indicative of any port or SAN issues.
When I run this command in every XIO, it always shows parameter Link-Failure count =1. What does it imply? What issue can cause what error for these parameters? A brief note would be great. Thanks.   xmcli (idigit)> show-targets-fc-error-counters                                                                                                                                Name       Index Cluster-Name Index Dumped-Frames Sync-Loss Signal-Loss Invalid-Crc Link-Failure Prim-Seq                                                                 X1-SC1-fc1 1     XIO                  1               0                       0              0                     0                1                 0                                                                           X1-SC1-fc2 2     XIO                  1               0                       0              0                     0                1                 0                                                                           X1-SC2-fc1 5     XIO                  1               0                       0              0                     0                1                 0                                                                          X1-SC2-fc2 6     XIO                  1               0                       0              0                     0                1                 0   
XtremIO: FC Error Link Failure