Knowledge Base

The VMware Knowledge Base provides support solutions, error messages and troubleshooting guides
 
Search the VMware Knowledge Base (KB)   View by Article ID
 

Physical Link Down with Loss of Redundancy (1009542)

Details

Summary

The event indicates that one or more portgroups in the ESX host has lost the last redundant uplink to the physical network. Portgroups are still connected and have only one uplink remaining.

Example

If vmnic1 is one of the two uplinks remaining on vSwitch0 and the VM Network is the only portgroup connected to this vswitch, the following error occurs if vmnic1 goes down:

Lost uplink redundancy on virtual switch "vSwitch0". Physical NIC vmnic1 is down. Affected portgroups: "VM Network"

Impact

The current working uplink is a single point of failure for the reported portgroups and might render the following services unavailable: virtual machines, service console, VMotion, NFS, iSCSI, and Management Services.

Solution

To determine the actual failure or to eliminate possible issues:

  1. Connect to ESX through SSH or the console:

    1. Identify the available uplinks:

      esxcfg-nics -l

    2. Remove the reported vmnic from the portgroups:

      esxcfg-vswitch -U <affected vmnic#> <affected vSwitch>

    3. Link available uplinks to the affected portgroups:

    esxcfg-vswitch -L <available vmnic#> <affected vSwitch>

  2. Check the status of the vmnic from the VMware vSphere client or the ESX service console.

    • To check the status from the vSphere client:
      1. Select the ESX host and click the Configuration tab.
      2. Click Networking.
      3. The vmnics currently assigned to virtual switches are displayed in the diagrams. If a vmnic displays a red X, that link is currently down.

    • To check the status from the service console, run the following command:

      [root@server root]# esxcfg-nics -l

      The output that appears is similar to the following:

      Name PCI Driver Link Speed Duplex Description
      vmnic0 04:04.00 tg3 Up 1000Mbps Full Broadcom BCM5780 Gigabit Ethernet
      vmnic1 04:04.01 tg3 Up 1000Mbps Full Broadcom BCM5780 Gigabit Ethernet


      The Link column specifies the status of the link between the network adapter and the physical switch. The status can be either Up or Down. If there are several network adapters. Some are up and some down, so you might need to verify that they are connected to the intended physical switch ports. This can be done by bringing down each of the ESX host's ports on the physical switch and running the esxcfg-nics -l command to observe which vmnic is affected.

  1. Check that the vmnic referred to in the event message is still connected to the switch and configured properly:

    1. Make sure that the network cable is still connected to the switch and to the host.

    2. Check that the switch connected to the system is still functioning properly and has not been inadvertently misconfigured. Refer to the switch documentation for details.

    3. Check for activity between the physical switch and the vmnic. This might be indicated either by a network trace or activity LEDs.

    4. Check for network port settings on the physical switch.

  1. To reconfigure the service console IP address if the affected vmnic is associated with a service console, see How to configure networking from the Service Console command line (1000258).

If the issue is due to your hardware, please contact your hardware vendor for a replacement.

It is important to fix this issue as soon as possible, as your ESX host is now working with a single point of failure at the networking layer.
 
For ESXi 4.x commands please refer to vSphere Command-Line Interface Installation and Reference Guide.

Note: These alarm can also be triggered if there is a limit placed on the the Broadcast traffic on the physical upstream switches. ESX/ESXi hosts rely on Broadcast Traffic and if there are limits set, it may cause flapping on the vmnic during vMotion.

Update History

02/24/2012 - Added note about broadcast traffic in the Solutions section

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.

Feedback

  • 9 Ratings

Did this article help you?
This article resolved my issue.
This article did not resolve my issue.
This article helped but additional information was required to resolve my issue.
What can we do to improve this information? (4000 or fewer characters)
  • 9 Ratings
Actions
KB: