Warning message

  • Cisco Support Forums is in Read Only mode while the site is being migrated.
  • Cisco Support Forums is in Read Only mode while the site is being migrated.

Odd behavior with Nexus in failover recovery?

Unanswered Question
Apr 11th, 2014
User Badges:


Not quite sure what to make of this.


We have a couple of esx servers that have one 10G nic in Nex1 and a second in Nex 2. The links are not port channeled. The two nexus switches are linked by two 10g connections channeld and vpc'ed .  Each nexus has two 1G connections Po'ed to a 3750 (our main access switch).

When we shut down one nexus all is good. No loss of connectivity, maybe a little blip but for the most part all is good.

When we bring up the shutdown nexus we are good UNTIL the nex actually comes on line. Then all the nodes lose connectivity for about 30-60 seconds.

The only thing we see in the logs is this.. last 9 seconds (as opposed to 30-60) but the timing is similar. (eth1/47 is one of the interswitch trunks)


%ETHPORT-5-IF_UP: Interface Ethernet1/47 is up in mode trunk
%ETHPORT-3-IF_ERROR_VLANS_SUSPENDED: VLANs 1,34 on Interface port-channel5 are being suspended. (Reason: vPC
peer is not reachable over cfs)


and 9 seconds later they are unsupended

ERROR_VLANS_REMOVED: VLANs 1,34 on Interface port-channel5 are removed from suspended state.


I dont know if this is normal but it would be nice if we could have two switches for HA .







  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Andrew Cormier Sat, 04/12/2014 - 05:27
User Badges:

Thanks Sean

I had enabled auto-recoverey on both switches yesterday but no luck.

The odd thing is (and I tested again). If I reboot switch 2 and ping one of the host AND ping switch 2 I see host is up and switch  down (normall). The second switch 2 starts replying to pings the host goes offline for about a minute. It is like switch one is saying "OH, my VPC peer is back, I am going to shut down my ports and wait until the all the vpc's are up"

Andrew Cormier Sat, 04/12/2014 - 05:37
User Badges:

NOTE: We see the same behavior regardless of which switch is restarted. I am wondering if this is related to role priority? Stumped :(


This Discussion