Unable to Add a Physical Adapter to a vSphere Distributed Switch That Has Network I/O Control Enabled

You might be unable to add a physical adapter with low speed, for example, 1 Gbps, to a vSphere Distributed Switch that has vSphere Network I/O Control version 3 configured.

Problem

You try to add a physical adapter with low speed, for example, 1 Gbps, to a vSphere Distributed Switch that is connected to physical adapters with high speed, for example, 10 Gbps. Network I/O Control version 3 is enabled on the switch and bandwidth reservations exist for one or more system traffic types, such as vSphere management traffic, vSphere vMotion traffic, vSphere NFS traffic, and so on. The task for adding the physical adapter fails with a status message that a parameter is incorrect.

A specified parameter was not correct: spec.host[].backing.pnicSpec[]

Cause

Network I/O Control aligns the bandwidth that is available for reservation to the 10-Gbps speed of the individual physical adapters that are already connected to the distributed switch. After you reserve a part of this bandwidth, adding a physical adapter whose speed is less than 10 Gbps might not meet the potential needs of a system traffic type.

For information about Network I/O Control version 3, see the vSphere Networking documentation.

Solution

1. In the vSphere Client, navigate to the host.
2. On the Configure tab, expand the System group of settings.
3. Select Advanced System Settings and click Edit.
4. Type the physical adapters that you want to use outside the scope of Network I/O Control as a comma-separated list for the Net.IOControlPnicOptOut parameter.
   For example: vmnic2,vmnic3
5. Click OK to apply the changes.
6. In the vSphere Client, add the physical adapter to the distributed switch.