Distributed Port Mirroring across hosts in same vDS

[jmapt]

Hello:

I have two hosts (esx01 and esx02) running ESXi 5.5 that are connected to the same vDS 5.1.  I have no issues passing traffic between VM's that are on the different hosts and in the same port group, so I know the vDS is doing what it is supposed to.  Each host has 8 vmnic's and the vDS has 8 uplinks, all set to active.

However, when I setup a distributed port mirroring on the vDS and choose a source port and destination port, I only get the mirrored traffic on the destination port if the ports are on the same host.  If the source and destination are on different hosts, no mirror traffic is received.

I have sort of worked around it by using the following https://everythingshouldbevirtual.com/vmware-vds-rspan-port-mirroring, however, that ends up giving me a lot of duplicated packets when I attach it to a single uplink (presumably as the switch is seeing the traffic ingress/egress on both vmnic's in the vDS uplink?  For each packet I see 8 duplicates.

But it seems to me that this should "just work" without having to do anything switch side.  I've also tried looking at: vSphere 5.1 – VDS Feature Enhancements – Port Mirroring – Part 3 | VMware vSphere Blog - VMware Blog..., but with that it seems those are in completed separated vDS which in that case an RSPAN makes sense at the switch level to pass the traffic.  But in my case it is a single switch sitting between two hosts that are connected to the same vDS.

Any thoughts or directions to help guide me to the answer would be greatly appreciated!

Josh

[sajal1 · Accepted solution]

Hello jmapt,

Please note the following:

Page 152:

Distributed Port Mirroring:  Mirror packets from a number of distributed ports to other distributed ports on the same host. If the source and the destination are on different hosts, this session type does not function.

And :

vMotion Compatibility:

Port mirroring between distributed ports can only be local. If the source and destination are on different hosts due to vMotion, mirroring between them will not work. However, if the source and destination move to the same host, port mirroring works.

http://pubs.vmware.com/vsphere-55/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-551-networ...

Though vDS seems to be a single switch essentially it is not. The control plane is single and is controlled from vCenter but the actual data plane in at the host level and each host has its own Data Plane for the vDS. So underlying at the data plane they are different switch running on different hosts.