Intermittent slowness due to high network port utilization

Applies to

Issue

• Intermittent slowness is reported while accessing the share/volume.
• Applications may run fine on one LIF but the other LIF is slow on a different node, port, or ifgrp
• The network team may give an alert of 100% port utilization on a NIC
• High port utilization observed in Grafana/AIQUM monitoring tool.
  • In Harvest this can be seen under the Harvest - cDOT / NetApp Detail: Network - Details view
• statistics lif show list increase in sent and receive data
  • The statistics show-periodic command with interval of 1 shows per-LIF throughput at intervals such as 1 second in the example below
  • The iscsi_lif object is required if using iSCSI, otherwise use the lif object for CIFS/NFS

Example: 

cluster1::> statistics lif show
cluster1 : 12/31/1969 16:00:04
                                Recv                Sent                
                          Recv  Data   Recv   Sent  Data   Sent Current
         LIF    Vserver Packet (Bps) Errors Packet (Bps) Errors    Port
------------ ---------- ------ ----- ------ ------ ----- ------ -------
node2_clus_1    Cluster      3   536      0      3   338      0     e0a
node2_clus_2    Cluster      3   398      0      3   287      0     e0b
node1_clus_2    Cluster      3   338      0      3   536      0     e0b
node1_clus_1    Cluster      3   287      0      3   398      0     e0a 

Cluster::> set diag

Cluster::*> statistics show-periodic -object {iscsi_lif|lif} -counter recv_data|sent_data -instance <lif> -interval 1
Cluster: iscsi_lif.iscsi: 10/27/2022 14:42:52
     recv     sent    Complete    Number of
     data     data Aggregation Constituents
 -------- -------- ----------- ------------
  113.9MB  115.8MB      n/a      n/a