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Setting Up a Link Aggregation

3 minute read.

Last Modified 2024-08-21 10:32 EDT

In general, a link aggregation (LAGG) is a method of combining (aggregating) multiple network connections in parallel to provide additional bandwidth or redundancy for critical networking situations. TrueNAS uses lagg(4) to manage LAGGs.

Before making network interface changes:

Stop running apps.
Power off running virtual machines (VMs).
Remove active NIC devices for VMs.

Sharing services such as SMB that use the IP address(s) assigned to the primary interface might cause issues with testing network changes. To resolve issues, stop sharing services such as SMB, make the interface change and test the connection, and when complete restart the service.

To set up a LAGG, go to Network, click Add on the Interfaces widget to open the Add Interface screen, then:

Select Link Aggregation from the Type dropdown list. You cannot change the Type field value after you click Save.
Figure 1: Add Interface
Enter a name for the interface using the format bondX, where X is a number representing a non-parent interface. Assing the first LAGG interface bond0.
You cannot change the Name of the interface after clicking Apply.
(Optional, but recommended) Enter any notes or reminders about this particular LAGG interface in Description.
Select the protocol from the Link Aggregation Protocol dropdown. Options are LACP, FAILOVER, or LOADBALANCE. Each option displays additional settings.
Figure 2: Add Interface Settings

LACP
LACP is the most common protocol for LAGG interfaces based on IEEE specification 802.3ad.
In LACP mode, the interfaces negotiate with the network switch to form a group of ports that are all active once. The network switch must support LACP for this option to function.
a. Select the hash policy from the Transmit Hash Policy dropdown list. LAYER2+3 is the default selection.
b. Select the LACPDU Rate Option:
SLOW (default) sets the heartbeat request to every second and the timeout to a three-consecutive heartbeat loss that is three seconds.
FAST sets the timeout rate at one per second even after synchronization. FAST allows for rapid detection of faults.

FAILOVER
Select FAILOVER to send traffic through the primary interface of the group. If the primary interface fails, traffic diverts to the next available interface in the LAGG.

LOADBALANCE
Select LOADBALANCE to accept traffic on any port of the LAGG group and balance the outgoing traffic on the active ports in the LAGG group. LOADBALANCE is a static setup that does not monitor the link state or negotiate with the switch.
Select the Transmit Hash Policy option from the dropdown list. LAYER2+3 is the default selection.
Select the interfaces to use in the aggregation from the Link Aggregation Interface dropdown list.
(Optional) Click Add to the right of Aliases to show additional IP address fields for each additional IP address to add to this LAGG interface.
Click Save when finished.
Test the network change when prompted.

Setting Up a Link Aggregation

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