Unifi USW-24-Pro / Unraid running ZFS - low speed on the SFP+ ports

Hello everyone, I would need a bit of help with some odd thing.

I’m running at home a USW-24-Pro POE, connecting my PC to my Unraid server via the 2 SFP+ ports (using SFP+ transceiver modules). Unraid is running a raidz pool and together with the 10G network cards on both my PC and Unraid, I was used to see rather very good transfer speeds.

Since some time though, my speeds are max out at around 100-110MB/s.

Not sure what changed and why I’m unable to go higher. I plugged my PC and Unraid via a Netgear GS110EMX using the 2x 10G ports… speed goes back up to what I was used to see.

Therefore I would suspect something is going on with the USW. On the USW side, both SFP+ ports have the link speed set manually to 10Gbps. The unraid is on a different VLAN, but that shouldn’t affect it.

I am no network guru, but I would say I have some basic knowledge of how things should work.
Any ideas of what could go wrong here?


Quick update… after some tests today, I have narrowed it down to some VLAN issue.
My PC and the server are in 2 separate VLANs. Move them to same VLAN, transfer speed goes back to 10Gbps. Move them back to their corresponding VLANs, speed drops to 1Gbps.

Now I need to figure it out where this limit comes from.

I’m curious to know what the fix is once you figure it out. Please be sure to report back.

Sure thing.

So… apparently I’ve done something wrong. What exactly… I can’t tell.

My setup was/is the following:
Pfsense ->2x 1Gb/s (LAG) → USW24.
USW24 → 10Gb/s → PC (x.x.1.1 network)
USW → 10Gb/s → Unraid (x.x.3.1 network)

As far as I was told, this setup apparently was not suppose to work at full 10Gb/s speed due to the 1Gb/s connection to the router .

As “changes” to the setup, nothing exceptional happed - at least counting from when I’ve noticed that the speed dropped to 1Gb/s. I mean, I’m running this since unifi still had the “old” interface. Did also some updates to my unraid… but kind of that was it. In fact, in my mind was that maybe something to the unraid server happened after some major update, since running ZFS was not something actually officially supported.

At this stage, I’m kind of out of ideas. I understand that I’ve done something wrong in the configuration at some point…but without more data I cannot do more in finding out. The only sure thing that I know are… my PC was in the x.x.1.1 network… and the unraid was under a x.x.3.1 network… and I also have “video proof” of the 10Gb/s speeds (i mean the 10Gb/s speeds are kind of hard not to notice).

Anyway, at this stage both PC and unraid are running under same VLAN, full 10Gb/s speeds… and all is good. It will probably remain a mystery as in “what the hell did I do”… so probably I will have to satisfy with that.

What is doing the routing between the VLANs? It sounds like it’s your pfsense router, in which case all traffic between the VLANs will be going over the 1Gb link to pfsense and back.