With Network I/O control (NIOC), you can adjust the bandwidth of your vSphere 7 networks. You can set different bandwidths for specific types of traffic. Once you enable NIOC on vSphere Distributed vSwitch, you'll be able to set shares according to your needs.

There are separate models for system traffic (vMotion, fault tolerance, vSAN, etc.) and for VM traffic. The main goal of NIOC is to ensure that you have enough bandwidth for your virtual machines (VMs) and that you can control their resource allocation while still preserving sufficient resources for your system traffic.

I'm sure you already know this, but in order to use NIOC and vDS, you'll need vSphere Enterprise Plus licensing.

VMware vSphere 7 Distributed vSwitch (vDS) is version 7 of vDS. Version 7 of vDS introduced a new feature for VMware NSX product integration—NSX Distributed Port group. The previous version of vDS, 6.6.0, introduced the MAC Learning capability.

To create a new vDS, click the Networking icon (the globe). Then right-click Datacenter object and select New vDS. Select Configure > Properties to check the properties.

VMware vSphere 7 Distributed Switch properties

VMware vSphere 7 Distributed Switch properties

How can vDS be upgraded from the previous release?

If you have upgraded recently from the previous release of vSphere, you can upgrade your vDS via the UI. We'll show you that later. Note that there is short downtime for the VMs attached to the switch.

Right-click your vDS and select > Upgrade > Upgrade Distributed Switch.

Upgrade VMware Distributed Switch

Upgrade VMware Distributed Switch

If you're running a fresh installation of vSphere 7 and creating a new vDS, you still have the option of creating previous versions of vDS, such as vSphere 6.5 or 6.7. You may need to ensure compatibility with the rest of your infrastructure, which might still be running older versions of vSphere.

vSphere 7 and the option to create a different version of vDS

vSphere 7 and the option to create a different version of vDS

Where should you enable NIOC?

You need to enable NIOC on each vDS. From Networking, select the vDS. Then select Actions > Settings > Edit Settings.

Enable NIOC on vSphere 7 vDS

Enable NIOC on vSphere 7 vDS

This opens a pop-up window where you can use the drop-down menu to enable or disable NIOC. NIOC is enabled by default.

Enable NIOC drop down menu

Enable NIOC drop down menu

The traffic types are all set to 50 shares except the VM traffic. No reservation or limits are set by default.

The main vSphere features for which network traffic can be configured are:

  • Management networking traffic
  • Fault tolerance (FT)
  • NFS
  • vSAN
  • vMotion
  • vSphere replication
  • vSphere data protection backup
  • Virtual machine

Here is the view of the system traffic and the default values. You can see that by default, all system types are at 50, while the VM value is at 100.

VMware vDS system traffic default values

VMware vDS system traffic default values

You can click the Edit button after selecting the type of traffic, and then modify the values by selecting Custom.

Configure shares reservations and limits for different traffic types

Configure shares reservations and limits for different traffic types

The allocation parameters for the different traffic types are:

  • Shares—Value from 1 to 100, where the maximum 100 is the priority of a traffic type compared to the other traffic types that are active on the same physical adapter.
  • Reservation—Minimum bandwidth is in Mbps. This is the bandwidth guaranteed on a simple physical adapter.
  • Limit—Sets the maximum allowed bandwidth, in Mbps or Gbps, that the traffic type can consume on a single physical adapter.

You can also create new resource types via the menu just below system traffic. Click the Network resource pools menu link and then click Add. This will create a new network resource pool that will have a reservation quota. You can then assign a VM to that pool.

This group basically takes off bandwidth from the Virtual Machine system type, so you would need to set up a bandwidth reservation for that group first.

Create new network resource pool in vSphere 7

Create new network resource pool in vSphere 7

This is the main principle of NIOC in vSphere 7. NIOC has been around since vSphere 5. The latest version is version 3, which has improved network resource reservation and allocation across the entire switch.

NIOC version 3 lets you configure bandwidth requirements for VMs. You can also use network resource pools where you can assign a bandwidth quota from the aggregated reservation for the virtual machine traffic and then allocate bandwidth from the pool to individual virtual machines.

While the configuration of the vDS and NIOC is only possible via vCenter Server, in case of a problem on your vCenter Server appliance (vCSA), the system functions and the rules are deployed on the individual ESXi hosts.

If you don't want to use NIOC for certain physical adapters, you can configure it as needed. It might be the case where this particular adapter is low capacity or low speed. You can do this in the advanced system settings.

Final words

VMware NIOC is a very powerful traffic shaping function available to all vSphere Enterprise Plus customers willing to control the network traffic for different traffic types. You can imagine, for example, having two physical 10 Gb (or 25, 50) NICs and allocating different traffic types for vSAN, backup network, FT, etc.

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Admins can implement Quality of Service (QoS) on network traffic. One example is the VMware vSAN environment, where they can set shares with a certain bandwidth available to vSAN. The physical adapter assigned for vSAN might otherwise become saturated during rebuild or synchronizations. This prevents vSAN traffic from consuming the whole capacity of the physical adapter.


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