An administrator has a two-node NetApp ONTAP cluster that is hosting FC LUNs for 90...

A QFULL response indicates that the storage controller’s FC target-port command queue has reached its supported capacity and cannot accept additional SCSI commands. With 90 hosts generating I/O, excessive fan-in to the existing target ports can exhaust available queue resources. Configuring additional FC target ports allows host connections and queued commands to be distributed across more storage-side target resources, reducing pressure on each individual target port. Increasing initiator queue depth would worsen the condition because hosts could submit more outstanding commands. Similarly, increasing target-port queue depth is not the appropriate administrator-controlled remedy presented here because the physical target adapter has defined queue limits. NetApp recommends planning host fan-in carefully to avoid QFULL conditions. Relevant topics include FC queue depth, target-port fan-in, QFULL responses, SAN scalability, and FC target-port design