Iperf3 values between windows WSL client and iperf3 server running in docker on TrueNAS EE

10G ethernet on both machines connected both into UDM Pro ports.

windows WSL → truenas: 4.68 Gbits/sec
truenas → Windows WSL: 800 Mbits/sec

Clearly, the bits flow faster downhill than uphill :wink:

My windows box has SSD, truenas has CMR drives and 128GB of cache.

Thought people might find these numbers interesting.

The transfer rate is measure with 1 second of transfer time so that means truenas didn’t have to write anything to the disk over that period since it caches up to 5 seconds in RAM.

iperf3 doesn’t read from or write to any drives or storage devices.

It actually has that as a new feature! But only if you ask for it.

On Windows you might get better results with iperf2. Iperf3 isn’t an “upgrade”, it’s a completely different platform. Historically iperf3 hasn’t had great performance on Windows - recent versions are better, but still …

That includes an excerpt from the iperf3 FAQ where they recommend using iperf2 on Windows.

I haven’t tried the Microsoft ntttcp tool on Linux (or FreeBSD).

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yeah, figured that out pretty quickly… :wink:

It’s interesting that the rates are NOT symmetric. Why is that???

I was running iperf3 from Debian in WSL.

I expected performance should be same in both directions, but it surprisingly wasn’t!