AUTO-ARCHIVED: Slow CIFS performance due to network congestion
Applies to
- ONTAP 9
- CIFS / SMB
Issue
- Microsoft Excel macro involving files on a CIFS share is slow
- Less than expected throughput
- Only one client affected
- No other applications are affected
- No error counters increased on related ports and ifgroups in ifstat -a
- Symptom does not change when Vscan and Fpolicy are disabled
- Packet trace indicates:
- SMB2 latency is increased unidirectionally from ONTAP to client
- Out of order packets and (fast) retransmissions
- Congestion control