The DCBXMode configuration in the Mellanox CX4 LX network adapter advanced properties can be configured to one of the two values -- 'Firmware in charge' and 'Host in charge'. 'Firmware in charge' is the default value. 

As a part of the Dell EMC Storage Spaces Direct Ready Node deployment, we recommend that you change this setting to 'Host in charge' and disable DCBX willing globally in the host OS. 

#Disable DCBX willing
Set-NetQoSDCBXSetting -Willing $false -Confirm:$false

#set Mellanox dcbxmode to host in charge; requires OOB Mellanox driver
Set-NetAdapterAdvancedProperty -Name 'SLOT 1 PORT 1' -DisplayName 'DcbXMode' -DisplayValue 'Host in charge'
Set-NetAdapterAdvancedProperty -Name 'SLOT 1 PORT 2' -DisplayName 'DcbXMode' -DisplayValue 'Host in charge'

What is the issue?

If you are using an older version of (than version 1.80) Mellanox driver and upgrade to version 1.80, the DCBXMode configuration setting changes to the default value which is 'Firmware in Charge'.

Where is the issue?

This is a change from Mellanox CX4 LX Driver version 1.80. 

Resolution or Workaround

You can use the Set-NetAdapterAdvancedProperty cmdlet to set the value of DCBXMode property back to 'Host in charge'