I have a question regarding a configuration we have in our Datacenter (see above)
The issue is with the Server configuration on the switch (Please note this is an ESX host with 2 NICs (active/active, same vSwitch), 1 NIC each connected to a different FEX)
Currently we have removed the 'channel-group x' from under the individual ports on each FEX and have full connectivity, i.e. no vPC configuration, how can this be working?
ESX uses per default the following NIC-teaming method:
"Route based on the originating port ID" - Also know as vSwitch port-based load-balancing, this method chooses an uplink based on the virtual port where the traffic entered the virtual switch
(check out this PDF: http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf)
With this method you don't need to configure a channel on your Nexus switches. If you configure a port-channel (vPC) you should reconfigure the ESX vSwitch teaming to "Route based on IP hash" and make sure your port-channels on the nexus are configured as static ports (mode on) because ESX is not able to do LACP.