This is what I don't understand. This is what I'm doing:
Mount SMB over 1GbE with UD.
Ensure no other processes are accessing the write or read disks. For example, writes to the target are >150 MB/s with preclear.
Test network performance between two systems with iperf3. I get sustained transfers of 115 MB/s over Cat-5E.
Use either rsync -avPR or rclone copy to perform the transfer.
Transfer speeds are about 40 MB/s max with rclone (tested transfers 1–10) and even worse with rsync