How to change or add Vmxnet3 link Speed

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

This article provides steps to change the vmxnet3 link speed via the .vmx file of the VM. (These changes can be seen in VMware vSphere 8.0.2 and later versions. We need not worry about the vmxnet3 driver version in this case.)

Resolution

To change the link speed from the .vmx file:

1. Shut down the virtual machine.
2. Locate the virtual machine's files.
3. Open the virtual machine's configuration file (.vmx) in a text editor.
4. Add the following line:
   ethernetX.linkspeed = "Y"
where, X is the virtual device whose link speed you want to change and Y is the link speed value you want in Mbps. 
5. When finished, save the changes by using the save option in the text editor.
6. Exit the text editor.

Alternatively, you can also edit/add this value to the VM via vSphere Client:

1. Shut down the VM.
2. Browse to the virtual machine in the vSphere Client.
   1. To find a virtual machine, select a data center, folder, cluster, resource pool, or host.
   2. Click the VMs tab.
3. Right-click the virtual machine and select Edit Settings.
4. Click VM Options.
5. Expand Advanced.
6. Under Configuration Parameters, click the Edit Configuration button.
7. In the dialog box that appears, click Add Row to enter the new parameter and its value.
   1. New Parameter - ethernetX.linkspeed, where X is the virtual device whose link speed you want to change.
   2. Value - Add the link speed value you wish to set in Mbps. 
8. Click OK.

Additional Information

1. It is important to note that, as of now, the link speed can take any value between 10 gigs and 65 gigs.
2. The default link speed value is 10 gigs.
3. If you set the link speed value to less than 10 gigs, the link speed value defaults to 10 gigs.
4. If you set the link speed value to greater than 65 gigs, the link speed value defaults to 10 gigs.