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How To Check Ring Buffer Size And Network Stat from ESXi

As a responsible VMware admin you might have experience in troubleshooting performance related issues and checking performance related issues cannot be avoided. I thought to write this article up for anyone has such requirement and how you can check the statistics related to Virtual Machines such as Ring Buffer Size, Tx, Rx drop packets, etc. 

You can use vSphere client or web client statistics graphs to get the idea and check the statistics in the first place. But it is hard to check the additional parameters from the traditional graphs and counters. That’s where these command line information and commands come in to play and having a great idea about this will be really valuable in a situation where you end up with the performance issues. This article explains how to use these commands in an ESXi shell to check the statistics for a particular Virtual Machine. Personally, it was really helpful for me to overcome and check stats in numerous times.  

Using Well Known  “net-stats”

I believe almost everyone aware of the “net-stats” command and we can retrieve bunch of valuable information in the ESXi.

net-stats -l” command will give you the output with Virtual Port Numbers, vSwitch Name relevant MAC address and Client Name in a similar output as below  

To narrow it down to a particular virtual machine use ” net-stats -l | grep “<virtual_machine_name>” ” command, it will only give you the relevant information specifically to that virtual machine

Check The Statistics Of A Virtual Machine With A VMXNET3 Adapter

Use “vsish -e get /net/portsets/DvsPortset-0/ports/<port_number>/clientStats” to view the statistics of the virtual machine. To understand please check the below output and you can see some valuable information including dropped transmitted and received packets

Tx and Rx summary can be viewed from the “vsish -e get /net/portsets/DvsPortset-0/ports/<port_numbers>/vmxnet3/rxSummary” (txSummary or rxSummary) command.

Ring buffer information such as running out of buffers , number of time buffers rings filled, number of times queue stopped and dropped can be examined from this output. 

Number of queues can be viewed from “vsish -e ls /net/portsets/DvsPortset-0/ports/<port_number>/vmxnet3/rxqueues/” (rxqueues and txqueues) command

Ring status can be viewed from “vsish -e get /net/portsets/DvsPortset-0/ports/<port_number>/vmxnet3/rxqueues/0/status” (rxqueues and txqueues) command. Number of queues, size of the queues, index data ring size can be viewed from the this command

For client server communication error/ packet drops can be observed using iperf tool. There will be a different post for the iperf tool usage, it is out of scope from the ESXi layer. 

Article Short Link: https://tcrum.net/Check-Ring-BufferSize

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Aruna Fernando

"Sharing knowledge doesn't put your job at risk - iron sharpen iron" I heard this and it's true.

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