82MB/sec is good assuming it doesn't take into account the sum of the read speed and write speed.Okay, I tried to copy a 30GB-file from a USB 3.0 stick (260MB/Sec read, 170MB/sec write to/from the SSD) as well as from the internal SSD, but the problem remains.
By the way: Copying a large file from one dataset to another with the Windows client (so, copying from one share to the other), works flawlessly at about 82MB/sec.
I just realized, I didn't answer an earlier question: I don't use deduplication on the dataset, I'm copying the bis image files to/from and only use the standard lz4 compression on all datasets.
Copying from a dataset to another dataset, means Freenas is not updating the link of the files, so this is good as it will have to travel across the network.
Also doing a read and write from the same array add latency, hence lower speed.
It does however take out the loop the SSD and USB 3.0.
Do you have a spare disk you can mount in Freenas and perform a copy as you just did, from one volume to the other over the network.