Changing the network teaming failback delay fails in ESXi

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Changing the failback delay fails
• Setting the failback delay to any other value does not work.

Environment

VMware vSphere ESXi 6.7

VMware vSphere ESXi 6.5

VMware vSphere ESXi 7.0

VMware vSphere ESXi 8.0

 

 

 

Cause

Because of a teaming policy, if an uplink goes down, connections are switched to another uplink in the team. When the first one goes up again, connections are immediately restored. This can cause packet loss when a connection is not stable and goes up/down several times for example when a switch starts.

To modify the TeamPolicyUpDelay, from vSphere go to Configuration > Advanced Settings > Net > Net.teampolicyupdelay. The default is set to 100 ms.

A configuration option, Net/TeamPolicyUpDelay is added to change the threshold in milliseconds (ms). At start up, the very first up event is not delayed. This setting delays the up notification. When an up event is received, a timer is triggered to notify this. If a down event occurs when the trigger is pending, then it is cancelled.

Resolution

This is resolved in ESXi 6.7 P02

Additional Information

While this issue is resolved in ESXi 6.7 P02, it is important to note that the configuration option causing the issue remains valid in ESXi 7.0, ESXi 8.0.

The resolution addresses the behavior under certain conditions rather than the Configuration setting itself. Therefore ESXi 7.0 and ESXi 8.0 included in impacted

environment list to ensure clarity. 

 

 

Kindly refer to NIC Teaming Policy Documents below for further details 

https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.networking.doc/GUID-4D97C749-1FFD-403D-B2AE-0CD0F1C70E2B.html

NSX-T Perspective:

++++++++++++++++

Please note that the information provided in this section is NSX-T perspective.
If NSX is running on this host and using NVDS, You can also apply these changes using below command from ESXi root login. 

nsxcli -c set vswitch runtime TeamPolicyUpDelay "value"

Example
nsxcli -c set vswitch runtime TeamPolicyUpDelay 600000. 

However, this will take effect at runtime and will not persist after the host rebooted the value will reset to its default. 

To persists the change, please follow the steps below:

Option 1
++++++++

1] Make changes from ESXi via vSphere console -pick host > Configure > Advanced system Settings > Net.TeamPolicyUpDelay > edit (default is 100) And modify/set the value you want to and save by clicking ok. 

2]  Then reboot the host for the changes to take effect 

3] Once node back online, ssh to host with root and verify setting using below command  

nsxcli -c get vswitch runtime

Option 2
+++++++++

1]Make changes from ESXi via command line with below command 

esxcli system settings advanced set -o /Net/TeamPolicyUpDelay --int-value xxx

Example: esxcli system settings advanced set -o /Net/TeamPolicyUpDelay --int-value 300000

[In this case then you don't need to reboot host. ]

2]ssh to host with root and verify setting using below command  

nsxcli -c get vswitch runtime

Note: N-VDS is not supported on NSX 4.X version. With the release of VMware NSX 4.x N-VDS is not supported for ESXi hosts anymore.
However, if you are still using NVDS or have already migrated to VDS, this change is being made directly to ESXI and will apply to both.