Question 1
An administrator has a two-node NetApp ONTAP cluster that is hosting FC LUNs for 90 SAN hosts. The hosts are experiencing occasional performance problems and receiving QFULL responses from the cluster nodes.
Which action would resolve this issue?
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