VMXNet3 "Disable Rx queuing" messages in vmkernel.log

Products

• VMware vSphere ESXi

Issue/Introduction

The purpose of this KB is to reduce confusion on what these messages mean, and provide documentation on it.

Symptoms:
You see the messages below in the vmkernel.log files during VM bootup or snapshot operations: 
 
YYYY-MM-DDTHH:MM:SS.Z cpuxx:8640120)Vmxnet3: 17293: Disable Rx queuing; queue size 256 is larger than Vmxnet3RxQueueLimit limit of 64.
YYYY-MM-DDTHH:MM:SS.Z cpuxx:8640120)Vmxnet3: 17651: Using default queue delivery for vmxnet3 for port 0x7xxxxxxx.

Environment

VMware vSphere ESXi 6.5

Cause

This message is related to PXE boot.  'Burst queueing' is being disabled when the vmxnet3 is being connected/re-connected to vSS/vDS port (e.g. during guest OS non-PXE bootups, or snapshots). This message can be safely ignored. 

Resolution

This is an expected behavior for normal VM boot operations. 
Documentation on Vmxnet3 Rx Burst Queuing feature and how to configure it

Quote: 
"VMXNet3's burst queueing should in general only be used if it is no longer possible to increase vNIC's Rx ring sizes.  This is the case during PXE booting using VMXNet3"