Performance hit on upgrade to ONTAP 9.7+ due to lack of TCP Segmentation Offload (TSO)

Applies to

• ONTAP 9.7 - 9.7P7
• Systems with interface groups configured with intercluster or node-management LIF(s) 

Issue

• TCP Segmentation Offloading (TSO) not available for certain interface groups while on ONTAP 9.7
• TSO stats zero or not incrementing in system node run -node <node> ifstat <port> for affected interface groups

-- interface  a0a  (33 days, 13 hours, 19 minutes, 43 seconds) --

RECEIVE
(...)
TRANSMIT
 Total frames:    22322m | Frames/second:    7700  | Total bytes:      1225g
(...)
 TSO non-TCP drop:    0  | Split hdr drop:      0  | Timeout:             0 
 TSO segments:        0  | TSO bytes:           0  | TSO6 segments:       0 <<< TSO Segments is 0 or not increasing

• Increased network/nblade utilization in performance statistics
  • The increase in network/nblade utlization may result in LACP ports flapping
    • 'net.ifgrp.lacp.link.inactive' events in the event log reflect this symptom
• Significant performance difference in write and read throughput might be noticed