Both machines are easily capable of reaching around 2.2Gbps. I can’t reach full 2.5Gbps speed even with Iperf. I tried some tuning but that didn’t help, so its fine for now. I used iperf3 -c xxx.xxx.xxx.xxx
, nothing else.
The slowdown MUST be related to ZFS, since LVM as a storage base can reach the “full” 2.2Gbps when used as a smb share.
Nevermind, I am an idiot. You’re comment gave me thought and so I checked my testing procedure again. Turns out that, completly by accident, everytime I copied files to the LVM-based NAS, I used the SSD on my PC as the source. In contrast, everytime I copied to the ZFS-based NAS, I used my hard driver as the source. I did that about 10 times. Everything is fine now. THANKS!