Synology adaptive load balancing - mac flapping

[chris-doro]

We've setup a Synology with Adaptive Load Balancing on the Heartbeat-interfaces (I was told LACP is not possible for the heartbeat).
We have LACP on the productive interfaces of the Synology and Cisco-switches C9300.
But ALB causes permanent MAC-flapping on the Cisco-switches C9300.
I am not sure it this is stable...
Any suggestions?
Thanks.

[M02@rt37]

Hello @chris-doro,

ALB dynamically balances outgoing traffic across all available network interfaces, which can lead to MAC address changes when the load balancing algorithm switches between interfaces.

Do you double check LACP configuration ans status C9300 side?

As you mentioned, LACP is not possible for the heartbeat interfaces. In this case, consider disabling ALB on the heartbeat interfaces and use a single active interface for the heartbeat. This can help eliminate MAC address changes and stabilize the heartbeat communication.