@stephenw10:
Having a shared IRQ should not prevent the NICs from working. Having disabled msix for all pci devices it's likely to have more of an effect (I would have thought) but even so it shouldn't stop all traffic.
I am unsure of your network configuration from your description and I have only experimental experience with a CARP setup so I can't really tell you what would happen. Since you will be thousands of miles away getting it wrong would be very bad so I would have to advise waiting for another opinion. :-
In the mean time giving us a network diagram would help greatly.
Steve
Thanks, Steve.
You're right, that having a shared IRQ should not lead to such results. Reading/googling further, I think next step is to exclude CARP interface from the bridge. As I stated, that is an old, inherited setup, and all 3 NICs are members of the bridge.