My understanding is that QNAP’s implementation requires symmetrical setups for SMB3. Their footnote is “ * The current version of SMB Multichannel does not support RSS, RDMA, NIC Teaming.”
So as I understand it this chokes the recipient to the slower of a single lane of the sender. This thread seemed relevant:
https://www.reddit.com/r/qnap/comments/127ui2o/the_new_qts_510_supports_smb_multichannel/
So in my use case My windows machines both physical and a VM send large Macrium image files to the server. Assuming the Macrium shares are SMB, then they can use this feature. Whereas I do not know if NAS to NAS transfers use SMB and would benefit.
In any case, if the receiver has only 1 nic, say 2.5Gb vs 2 x1Gb on the sending unit, then if the receiver is a QNAP NAS then there is no RSS so you get 1Gb only.
Noting than you also need multi core machines to run RSS anyway.
I think…
I assume that if SMB does not work then the default transmission is the slowest lane anyway.
Regards