Hi. On Fri, Oct 05, 2018 at 03:14:15PM +0100, Adam Weremczuk wrote: > Hello, > > I have 2 servers running Proxmox 5.2 (based on Debian 9).
Have you considered using OpenVSwitch for the task? > I've connected Ethernet ports between them with a pair of cross over cables. Ok. > iface ens1f0 inet manual > > iface ens1f1 inet manual Not needed. ifupdown is smart enough to bring those up without these lines. > auto bond1 > iface bond1 inet static > slaves ens1f0 ens1f1 It's 'bond-slaves', not 'slaves' > address 192.168.200.1(2) > netmask 255.255.255.252 > bond_miimon 100 > # bond_mode 802.3ad > bond_mode balance-rr > bond_xmit_hash_policy layer3+4 Documentation/networking/bonding.txt.gz clearly states that: xmit_hash_policy Selects the transmit hash policy to use for slave selection in balance-xor, 802.3ad, and tlb modes. balance-rr and xmit_hash_policy do not play together. > Tried both 802.3ad and balance-rr modes. And predictably 802.3ad did not work for you. You're using cross-cable = you lack LACP Partner. No LACP probes = 802.3ad fails. > AFAIK only these 2 provide link aggregation. No. There is 'balance-tlb' that does it too, but it's useless in cross-over setup. Add any cheap unmanaged switch to the picture, and it will be different. > Unfortunately in either mode cross pinging fails with "Destination Host > Unreachable". Leaving aside '802.3ad' that will never work for you, let's focus on 'balance-rr'. Starting with something simple, have you confirmed via tcpdump that both links receive ICMP from the other host? > The same configuration works fine against managed switch ports (LACP/LAG). Adding a hint here, OpenVSwitch can be LACP Partner. Linux kernel can be Actor only. > So my question is why this is not working and whether it's possible at all? 802.3ad - both hosts are unable to negotiate links for ingress traffic. balance-rr - my best guess so far goes into ARP filtering direction. Reco