Description
This article describes the behavior of LACP in an HA cluster.
Scope
The scenario is described as follows:
An aggregate link (LACP) is configured on both devices acting one as Master and the other one as Slave (Active - Passive mode). The aggregate link is comprised of the master's designated interfaces and an equal number of the slave's interfaces.
By default, in this configuration, it is not permitted that the Slave to participate in the LACP negotiation. In case it would be permitted and taking into account that the MAC address assigned to the cluster is the same for both members, then the HA could not work. This situation also applies to an HA cluster in Active–Active mode.
Solution
The way to prevent the Slave to participate in the LACP negotiation is by applying the following commands:
config system interface
edit port1_port2
set lacp-ha-slave disable <-
next
end
With this configuration, the subordinate unit's interfaces cannot accept any packets. As a consequence, a failover will take more time because the slave unit must perform an LACP negotiation before being able to receive and process packets.
Note: For version 7.2.1, lacp-ha-slave has been replaced with lacp-ha-secondary.
