I've setup a 2-nodes vSphere cluster. Each node is equipped with 4x1GE NICs. I have set a single vSwitch in each node, using all 4 vmnics as adapters and the following ports:
Management: vmKernel port -> Active on vmnic0, Standby on vmnic1-2-3
vMotion and FT -> Active on vmnic3, Standby on vmnic0-1-2
Workload -> Active on vmnic0-1-2-3
Route based on originating virtual port.
I know the solution is not idea, as best practices suggest to have a physically separated network for vMotion/FT, but still.
I noticed that no VM is mapped to vmnic3, so this appears to be used by vMotion/FT only.
However when FT is enabled (on a dummy WinServer machine doing nothing), I notice the following issues:
1) pings to/from that machine go unstable (up to 5ms)
2) capturing stats on the physical switch, I noticed the port physically connected to vMotion/FT NIC has an input rate of 300Mbps (which is expected), but I also notice the output rate of all ports connected to other vmnics go 300Mbps, like the physical switch flood FT traffic on all other ports. When disabling FT, traffic go back to small values on all NICs.
Why points 1 and 2 above?
EDIT: All ports are in the same VLAN. I know this is far from ideal, but still can't explain points 1 and 2 above