On S2D Clusters, here is a one-line PowerShell that I find useful to see which node is seeing the highest IOPS:
Get-StorageQosFlow | Sort-Object StorageNodeIOPs -Descending | ft InitiatorName, @{Expression={$_.InitiatorNodeName.Substring(0,$_.InitiatorNodeName.IndexOf('.'))};Label="InitiatorNodeName"}, StorageNodeIOPs, StorageNodeLatency, Status, InitiatorIOPS, @{Expression={$_.FilePath.Substring($_.FilePath.LastIndexOf('\SMB')+1)};Label="File"} -AutoSize