This is a basic configuration for DCB and PFC to use with Windows 2016 and „storage spaces direct“ on Dell EMC S4xxx switches. CoS class is set to 4.

conf t

int vlan 30
 description S2D
 ip address 10.10.10.10 255.255.255.0
 mtu 9216
 no shut
exit

dcbx enable

policy-map type qos TRUSTMAP
 class class-trust
  trust dot1p
 exit
exit

class-map type network-qos PFCMAP
 match qos-group 4
exit

policy-map type network-qos QOSMAP
 class PFCMAP
  pause buffer-size 100 pause-threshold 50 resume-threshold 10
  pfc-cos 4
 exit
exit

system qos
 service-policy input type qos TRUSTMAP
exit

interface range ethernet 1/1/1-1/1/12
 no flowcontrol receive
 no flowcontrol transmit
 switchport mode trunk
 switchport trunk allowed vlan 30
 service-policy input type network-qos QOSMAP
 mtu 9216
 priority-flow-control mode on
exit

exit

Config on Windows:

# Clear previous configuration
Get-NetQosTrafficClass |  Remove-NetQosTrafficClass
Get-NetQosPolicy | Remove-NetQosPolicy

# Disable the DCBx setting
Set-NetQosDcbxSetting -Willing $false -Confirm $true

# create Qos policies and tag each type of traffic with the relevant priority
# SMB PFC priority = 4
New-NetQosPolicy 'SMB' -NetDirectPortMatchCondition 445 -PriorityValue8021Action 4

# Set VLAN ID for SMB-NICs
Get-NetAdapter | ? Name -like '*SMB*' | Set-NetAdapterAdvancedProperty -RegistryKeyword 'VlanID' -RegistryValue 30 -Verbose
Get-NetAdapter | ? Name -like '*SMB*' | Get-NetAdapterAdvancedProperty -RegistryKeyword 'VlanID'

# Enable Priotity Flow Control (PFC) on a specific priority (5). Disable for others....
Enable-NetQosFlowControl -Priority 4
Disable-NetQosFlowControl 0,1,2,3,5,6,7

# Enable QoS on SMB-NICs
Get-NetAdapter | ? Name -like '*SMB*'| Enable-NetAdapterQos