samba - Sep 2016 - No increased throughput with SMB Multichannel and two NICs

Am 2016-09-06 10:41, schrieb Anoop C S via samba:
> 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

[...]AFAIK, the windows client only puts traffic on interfaces of same
speed and quality simultaneouslt[...]

I interpret this as "with two identical NIC-speeds at server-side and 
client-side it should result in double throughput".
On both hosts I've 2x1GBit/s NICs and Windows uses both(!) NICs (but not 
at full speed when multichannel is enabled). So I don't think my problem 
is related to this thread, beacuse if it is, Windows would choose only 
one NIC.

>> 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
>>

On Tue, Sep 06, 2016 at 03:56:14PM +0200, Daniel Vogelbacher via samba
wrote:
> 
> Am 2016-09-06 10:41, schrieb Anoop C S via samba:
> >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
> 
> 
> [...]AFAIK, the windows client only puts traffic on interfaces of same
> speed and quality simultaneouslt[...]
> 
> I interpret this as "with two identical NIC-speeds at server-side
> and client-side it should result in double throughput".
> On both hosts I've 2x1GBit/s NICs and Windows uses both(!) NICs (but
> not at full speed when multichannel is enabled). So I don't think my
> problem is related to this thread, beacuse if it is, Windows would
> choose only one NIC.
What do you have set for "aio read size"/"aio write size"
in your smb.conf ?

On 06.09.2016 19:39, Jeremy Allison via samba wrote:
> On Tue, Sep 06, 2016 at 03:56:14PM +0200, Daniel Vogelbacher via samba
wrote:
>>
>> Am 2016-09-06 10:41, schrieb Anoop C S via samba:
>>> 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
>>
>>
>> [...]AFAIK, the windows client only puts traffic on interfaces of same
>> speed and quality simultaneouslt[...]
>>
>> I interpret this as "with two identical NIC-speeds at server-side
>> and client-side it should result in double throughput".
>> On both hosts I've 2x1GBit/s NICs and Windows uses both(!) NICs
(but
>> not at full speed when multichannel is enabled). So I don't think
my
>> problem is related to this thread, beacuse if it is, Windows would
>> choose only one NIC.
> 
> What do you have set for "aio read size"/"aio write
size"
> in your smb.conf ?
> 
I don't have these options in my smb.conf.
Do you recommend any specific values?


Regards
Daniel Vogelbacher