Mac address flapping on Vmotion.

[nishantmelepat]

Hello

I am facing an issue, the ESX hypervisors connected to CISCO switch are getting mac address flapping. What we observed is, it is happening when a Virtual machine being migrated from one host to other host.

I can say its not specific to a single hypervisor host.   Here are the log which is coming on our Cisco switch.

Jan 19 07:18:03.423: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:56:92:0D:DE in vlan 130 is moving from port Gi7/3 to port Te5/1

Jan 19 07:18:26.739: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:56:00:02:74 in vlan 130 is moving from port Gi7/3 to port Te5/1

Jan 19 07:18:27.157: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:56:00:03:50 in vlan 130 is moving from port Gi7/3 to port Te5/1

Jan 19 07:18:45.127: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:56:00:03:6E in vlan 130 is moving from port Gi7/6 to port Te5/1

Jan 19 07:19:52.906: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:56:00:04:69 in vlan 130 is moving from port Gi7/6 to port Te5/1

Jan 19 07:20:56.114: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:56:92:37:E7 in vlan 140 is moving from port Gi7/6 to port Gi7/3

Any inputs, highly appreciated.  In the mean time, I am also working with Vmware support.

Thank you.

Nishant

[Ahmed_Selim]

Flapping error occurs when the same MAC address is coming from two different physical ports. This may occur, for example, if two physical ports are connected to different ESX hosts. 

To resolve this issue, ensure that Network Failover detection is set to Link Status Only. Do not use beacon probing with IP hash load balancing.

Please read the KB : VMware KB: VMware ESX/ESXi host network flapping error when Beacon Probing is selected

[nishantmelepat]

Hello Ahmed,

Thanks,

It is set to by default Link status only, also the hashing is route based on originating virtual port ID. 

Regards

Nishant