MLAG with VMware or HyperV - tons of DUP packets

[Eric_Burke]

We deployed our first MLAG scenario with 2 x670's at the core and with VMware 6.0 downstream. We had unusual amounts of what appeared to be packet loss, overall slowness and VM's showing online, then offline, etc. A packet trace revealed a TON of duplicate packets and retransmissions. When we took the second peer offline, these ceased. We've since confirmed that both sides of each MLAG are using L3 algorithm (IP HASH on vswitch), we removed all unused / standby adapters from the vswitch and we ensured that beacon probing was off. We otherwise followed the 2012 white paper from Extreme on deploying MLAG in an ESXi environment. Not sure if all of the duplicate traffic is expected in this config or if we're doing something wrong. Ideas?

[Ty_Kolff]

Eric,

We have not been configuring any LAG on our VMWare servers that are connected to an MLAG pair. We simply plug one NIC from the VMWare servers into each switch and leave the default VMWare option which I believe is 'Route based on originating port ID'

Here is another post discussing this:
https://community.extremenetworks.com/extreme/topics/dual-x670v-stacks-mlag-and-vmware-esx

[Eric_Burke]

Thanks for that. Did you leave your other connections in MLAG? For example, our design includes 8 standalone user switches (all configured as LACP L3_L4 via MLAG to the 670's), a couple of Windows servers (which we can use LACP on), etc. My guess is, that you probably have a bit more traffic spanning the ISC since traffic is likely to need to cross that link to reach its destination?

[Ty_Kolff]

Exactly. I just left the ports as single trunk ports that the VMWare servers are plugged into. On the VMWare side we left the default teaming option as 'Route based on originating virtual port ID' VMWare handles the failover.

I have this installed in a production environment and have tested failover on multiple servers. I was in the same position as you a few months back.

[Eric_Burke]

Thanks for the link Ty, I'll check it out...

BTW: Are you saying that on the Extreme side you're not settings those ports for MLAG either (just standalone trunks in the same VLANs on each side)? I get the feeling that's our problem - one side is a LAG and the other is not.

[Eric_Burke]

Thanks for the link Ty, I'll check it out...