[Samba] No increased throughput with SMB Multichannel and two NICs

[Anoop C S]

On Sun, 2016-09-04 at 11:42 +0200, Daniel Vogelbacher via samba wrote:
> Hello,
> 
> I'm running Samba 4.4.5 with enabled SMB Multichannel. The Linux
> server
> has two 1GBit/s NICs and for testing purposes I've shared a tmpfs
> mountpoint with 2GiB and ~2GiB large test-file.
> 
> My Windows 10 host has one dual-port 1GBit/s NIC, and if both
> interfaces
> are enabled, Get-SmbMultichannelConnection lists active multichannel
> connections to my Linux SMB server.
> 
> If I disable one NIC on Windows, the other NIC is used with ~1GBit/s
> when transferring the test-file from Linux to Windows.
> If I enable both NICs, instead of 2x1Gbit/s I only get ~500MBit/s per
> interface (but both interfaces are used).
> 
> So instead of doubling the throughput, traffic is split up between
> two
> interface half by half.
> 

This is mostly a Windows client-controlled behavior. Refer to the
following reply for a thread on similar subject for more details. 

https://lists.samba.org/archive/samba/2016-August/201841.html


> Is it possible to change this behaviour?
> 
> 
> Hardware infos on Linux:
> 
> 07:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network
> Connection (rev 03)
> 08:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network
> Connection (rev 03)
> 
> # uname -a
> Linux mz4 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2+deb8u3
> (2016-07-02) x86_64 GNU/Linux
> 
> /# /usr/local/samba/sbin/smbd --version
> Version 4.4.5
> 
> Hardware infos on Windows 10:
> Intel PRO/1000 PT Dual Port Server Adapter
> 
> 
> 
> Regards,
> Daniel Vogelbacher
>