Network connectivity to a RedHat 6.x virtual machine is lost after a vMotion migration

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Network connectivity to a RedHat 6.x virtual machine that uses a VMXNET3 network adapter is lost after a vMotion migration.
• You are unable to connect to a RedHat 6.x virtual machine that was migrated using vMotion.

Environment

VMware vSphere ESXi 5.5
VMware vSphere ESXi 5.0
VMware vSphere ESXi 5.1

Cause

This issue occurs when there is a TX and RX buffer overrun for the VMXNET3 adapter in a RedHat 6.x virtual machine.

Resolution

To resolve this issue, increase the TX and RX buffer size to their maximum values.

To increase the TX and RX buffer sizes in RedHat 6.x:

1. Open this file using a text editor:
   
   /etc/sysconfig/network-scripts/ifcfg-ethX
   
   Where X is the numeric identifier of the adapter using VMXNET3.
   
   
2. Add this line to the file:
   
   ETHTOOL_OPTS="-G ethX rx 4096 tx 4096"
   
   
3. Save and close the file.