You can configure Network I/O Control to allocate certain amount of bandwidth for traffic generated by vSphere Fault Tolerance, vSphere vMotion, and so on.

You can use Network I/O Control on a distributed switch to configure bandwidth allocation for the traffic that is related to the main vSphere features:

  • Management
  • Fault Tolerance
  • NFS
  • vSAN
  • vMotion
  • vSphere Replication
  • vSphere Data Protection Backup
  • Virtual machine
  • NVMe over TCP

vCenter Server propagates the allocation from the distributed switch to each physical adapter on the hosts that are connected to the switch.

Bandwidth Allocation Parameters for System Traffic

By using several configuration parameters Network I/O Control allocates bandwidth to traffic from basic vSphere system features.

Table 1. Allocation Parameters for System Traffic
Parameter for Bandwidth Allocation Description
Shares

Shares, from 1 to 100, reflect the relative priority of a system traffic type against the other system traffic types that are active on the same physical adapter.

The amount of bandwidth available to a system traffic type is determined by its relative shares and by the amount of data that the other system features are transmitting.

Reservation

The minimum bandwidth, in Mbps, that must be guaranteed on a single physical adapter. The total bandwidth reserved among all system traffic types cannot exceed 75 percent of the bandwidth that the physical network adapter with the lowest capacity can provide.

Reserved bandwidth that is unused becomes available to other types of system traffic. However, Network I/O Control does not redistribute the capacity that system traffic does not use to virtual machine placement.

Limit The maximum bandwidth, in Mbps or Gbps, that a system traffic type can consume on a single physical adapter.

Example of Bandwidth Reservation for System Traffic

The capacity of the physical adapters determines the bandwidth that you guarantee. According to this capacity, you can guarantee minimum bandwidth to a system feature for its optimal operation.

For example, on a distributed switch that is connected to ESXi hosts with 10 GbE network adapters, you might configure reservation to guarantee 1 Gbps for management through vCenter Server, 1 Gbps for vSphere Fault Tolerance, 1 Gbps for vSphere vMotion traffic, and 0.5 Gbps for virtual machine traffic. Network I/O Control allocates the requested bandwidth on each physical network adapter. You can reserve no more than 75 percent of the bandwidth of a physical network adapter, that is, no more than 7.5 Gbps.

You might leave more capacity unreserved to let the host allocate bandwidth dynamically according to shares, limits, and use, and to reserve only bandwidth that is enough for the operation of a system feature.

How to Allocate Bandwidth for System Traffic

Assign bandwidth for host management, virtual machines, NFS storage, vSphere vMotion, vSphere Fault Tolerance, vSAN, and vSphere Replication on the physical adapters that are connected to a vSphere Distributed Switch.

To enable bandwidth allocation for virtual machines by using Network I/O Control, configure the virtual machine system traffic. The bandwidth reservation for virtual machine traffic is also used in admission control. When you power on a virtual machine, admission control verifies that enough bandwidth is available.

Prerequisites

Procedure

  1. On the vSphere Client Home page, click Networking and navigate to the distributed switch.
  2. On the Configure tab, expand Resource Allocation.
  3. Click System Traffic.
    You see the bandwidth allocation for the types of system traffic.
  4. Select the traffic type according to the vSphere feature that you want to provision and click Edit.
    The network resource settings for the traffic type appear.
  5. From the Shares drop-down menu, edit the share of the traffic in the overall flow through a physical adapter.

    Network I/O Control applies the configured shares when a physical adapter is saturated.

    You can select an option to set a pre-defined value, or select Custom and type a number from 1 to 100 to set another share.

  6. In the Reservation text box, enter a value for the minimum bandwidth that must be available for the traffic type.
    The total reservation for system traffic must not exceed 75% of the bandwidth supported by the physical adapter with the lowest capacity of all adapters connected to the distributed switch.
  7. In the Limit text box, set the maximum bandwidth that system traffic of the selected type can use.
  8. Click OK to apply the allocation settings.

Results

vCenter Server propagates the allocation from the distributed switch to the host physical adapters that are connected to the switch.