This is a write-up of how I was able to get the multi-channel component of SMB 3 working with OMV using SAMBA and dual-gigabit NICs.

Requirements for server:

• Samba 4.9 (might work lower but I haven't tried)
• Dual NICs set to 'Balanced-tlb' bond mode (see OMV documentation under Network section)

Requirements for clients:

• SMB 3 (nothing before Windows 8)
• Dual NICs (do not need to be teamed/bonded) or
• NIC with RSS enabled ( single NIC will max out at single NIC LAN speed)

Directions:

Bond the NICs in the server (I set mine to 'balanced-tlb')

Add the followings lines to the additional section in the samba web config:

server multi channel support = yes

aio read size = 1 

aio write size = 1

Make sure you are connecting via SMB 3 or higher on the client and multi-channel is enabled. In powershell type:

Get-SmbClientConfiguration

Look for:

EnableMultiChannel : True

If not True run:

Set-SmbClientConfiguration -EnableMultiChannel $true

I also ran it with '-EnableBandwidthThrottling $false' but I don't know if this is necessary.

Run a file copy from the share to the client and run:

Get-SmbMultiChannelConnection

Check that you are connected to the server at one IP with two unique client IPs such as:

Server Name Selected Client IP     Server IP     Client Interface Index Server Interface Index Client RSS Capable Client RDMA Capable
----------- -------- ---------     ---------     ---------------------- ---------------------- ------------------ -------------------
omv         True     192.168.1.101 192.168.1.200 35                     5                      False              False
omv         True     192.168.1.102 192.168.1.200 6                      5                      False              False

Next run a robocopy with multithreading on some big files to test:

robocopy \\omv\test c:\test /MT:32

Results in Task Manager (hopefully).

Hope this works for you. Just figured it all out with some searching and trial and error.

For reference, I am using an onboard Intel 217 with an add-on Realtek 8111 PCI-E in the client and a dual Broadcom 5720 ($11 on ebay currently) in the server with a Cisco unmanaged consumer gigabit switch between them.