Just got a new server and will be setting up a DAC internet connection. Since the pci-e card actually has 2 sfp+ ports and my MikroTik CSS326-24G-2S+RM has 2 sfp+ ports I was thinking about using 2 DACS with bonding.

The switch supports LACP so was considering that but not sure if it actually results in increased bandwidth in the real world???

My goal is to improve bandwidth so my arrs stack doesn’t hog it all.

17 hours ago, wgstarks said:

but not sure if it actually results in increased bandwidth

I run 802.3ad (Mode 4/LACP) bonding on one of my servers and it works well in my experience. It does not create an aggregate 20Gbps bandwidth for single streams but it does allow for an extra 10Gbps of total bandwidth so that other clients can keep using services without bottle-necking each other. Just make sure you tackle the networking config changes in the right order so that you do not drop your network access.

Its also worth noting that LACP helps by adding headroom, but does not actually control or throttle anything. If you are experiencing starved bandwidth on other services while your arr stack is active you would want some QoS rules on either the switch or router to rate-limit or lower the priority on that traffic.

2 hours ago, CandleSir said:

Just make sure you tackle the networking config changes in the right order so that you do not drop your network access.

What is the order? I haven’t found a step-by-step.

Rule of thumb is downstream devices first, then the switch ports. Also worth making a quick backup of your network.cfg: cp /boot/config/network.cfg /boot/config/network.cfg.bak and I reassigned the MAC addresses when I did mine so if you do that, backup network-rules.cfg as well. It is worth checking the docs as I had a couple other things I was doing as part of the process that are not required, but here is my experience:

1. I reassigned my MAC addresses so my new dual SFP+ interfaces were eth0 and eth1, and my original single SFP+ was eth2.

2. Enable bonding on eth0, adding eth1 as a member and pick your bonding mode. For LACP that is Mode 4 but the Unraid help blurb is very descriptive.

3. Apply your changes and shutdown.

4. Enable LACP on the switch ports and then boot Unraid back up.

One thing worth mentioning: my original SFP+ (new eth2) stayed online as a normal bridge so I had a live connection the whole time while the bond came up. If you are bonding your only 2 ports it will be different so the order matters more for you. The link may drop after creating the bond on Unraid until the switch ports are configured and up.

Thanks I’ll still have an Ethernet nic that I’ll setup as eth3 for a back door if needed.