Use Load Balancing and Failover policies to determine how network traffic is distributed between adapters and how to reroute traffic in the event of an adapter failure.
The Failover and Load Balancing policies include the following parameters:
- Load Balancing policy: The Load Balancing policy determines how outgoing traffic is distributed among the network adapters assigned to a standard switch. Incoming traffic is controlled by the Load Balancing policy on the physical switch.
- Failover Detection: Link Status/Beacon Probing
- Network Adapter Order (Active/Standby)
In some cases, you might lose standard switch connectivity when a failover or failback event occurs. This causes the MAC addresses used by virtual machines associated with that standard switch to appear on a different switch port than they previously did. To avoid this problem, put your physical switch in portfast or portfast trunk mode.
Launch the vSphere Client and log in to a vCenter Server system.
- Log in to the vSphere Client and select a host in the inventory pane.
- Click the Configuration tab and click Networking.
- Select a standard switch and click Properties.
- Click the Ports tab.
- To edit the Failover and Load Balancing values, select the standard switch item and click Edit.
- Click the NIC Teaming tab.
You can override the failover order at the port group level. By default, new adapters are active for all policies. New adapters carry traffic for the standard switch and its port group unless you specify otherwise.
- In the Load Balancing list, select an option for how to select an uplink.
Option Description Route based on the originating port ID Select an uplink based on the virtual port where the traffic entered the standard switch. Route based on ip hash Select an uplink based on a hash of the source and destination IP addresses of each packet. For non-IP packets, whatever is at those offsets is used to compute the hash. Route based on source MAC hash Select an uplink based on a hash of the source Ethernet. Use explicit failover order Always use the highest order uplink from the list of Active adapters that passes failover detection criteria.
- In the Network failover detection list, select the option to use for failover detection.
Option Description Link Status only Relies solely on the link status that the network adapter provides. This option detects failures, such as cable pulls and physical switch power failures, but not configuration errors, such as a physical switch port being blocked by spanning tree or misconfigured to the wrong VLAN or cable pulls on the other side of a physical switch. Beacon Probing Sends out and listens for beacon probes on all NICs in the team and uses this information, in addition to link status, to determine link failure. This option detects many of the failures mentioned above that are not detected by link status alone.Note: Do not use beacon probing with IP-hash load balancing.
- Select Yes or No to notify switches in the case of failover.
If you select Yes, whenever a virtual NIC is connected to the standard switch or whenever that virtual NIC’s traffic is routed over a different physical NIC in the team because of a failover event, a notification is sent over the network to update the lookup tables on the physical switches. In almost all cases, this is desirable for the lowest latency of failover occurrences and migrations with vMotion.
Do not use this option when the virtual machines using the port group are using Microsoft Network Load Balancing (NLB) in unicast mode. No such issue exists with NLB running in multicast mode.
- Select Yes or No to disable or enable failback.
This option determines how a physical adapter is returned to active duty after recovering from a failure. If failback is set to Yes, the adapter is returned to active duty immediately on recovery, displacing the standby adapter that took over its slot, if any. If failback is set to No, a failed adapter is left inactive even after recovery until another active adapter fails, requiring its replacement.
- Set Failover Order to specify how to distribute the work load for adapters.
To use some adapters but reserve others for emergencies, you can set this condition using the drop-down menu to place them into groups.
Option Description Active Adapters Continue to use the adapter when the network adapter connectivity is available and active. Standby Adapters Use this adapter if one of the active adapter’s connectivity is unavailable. Unused Adapters Do not use this adapter.If you are using iSCSI Multipathing, your VMkernel interface must be configured to have one active adapter and no standby adapters. See the vSphere Storage documentation.Note: When using IP-hash load balancing, do not configure standby uplinks.