Cannot increase MTU setting for virtual machines running Solaris with VMXNET3 network interface

Products

• VMware vCenter Server

Issue/Introduction

You cannot increase the MTU setting for virtual machines running Solaris 10 or 11 as the guest operating system and using a VMXNET3 network interface. This error occurs even after successfully installing VMware Tools and restarting the virtual machine.

Environment

VMware vCenter Server 5.1.x
VMware vCenter Server 5.0.x

Resolution

Modify the virtual machine's /kernel/drv/vmxnet3s.conf file. Specifically, at the end of the section:

# MTU --
#
# Set MTU for each vmxnet3s# adapter.
#
# Minimum value: 60
# Maximum value: 9000
#
#MTU=1500,1500,1500,1500,1500,1500,1500,1500,1500,1500;

append the following:

MTU=9000,9000,9000,9000,9000,9000,9000,9000,9000,9000;

Then reboot the virtual machine.

Note: If the virtual machine is running Solaris 11, instead of modifying the /kernel/drv/vmxnet3s.conf file, you can change the network adapter from VMXNET3 to e1000.