[Samba] aio settings for samba 4.3

[Achim Gottinger]

Am 21.07.2016 um 20:56 schrieb Russell R Poyner:
> Jeremy,
>
> I think this is exactly a complex interaction between FreeBSD and 
> Samba. Best guess would be some system call that is fast in linux but 
> slow in FreeBSD holding things back.
>
> Russ
>
> On 07/21/2016 01:00 PM, Jeremy Allison wrote:
>> On Thu, Jul 21, 2016 at 12:23:01PM -0500, Russell R Poyner wrote:
>>> One more data point for comparison
>>>
>>> I installed the stock samba 4.2 rpm on a centos 7 machine and ran
>>> the same diskspd tests against a share configured with:
>>>     vfs objects = aio_pthread
>>>     aio read size = 1024
>>>     aio read size = 1024
>>>
>>>     smb2 leases = yes
>>>
>>> I get 27MB/s with 4k blocks and 145MB/s with 64k blocks. Disabling
>>> cacheing by passing the -h switch to diskspd lowered these to 72MB/s
>>> and 11MB/s. Which I view as 'close enough' to wire speed. Thus it
>>> seems that the dismal performance I see is associated with the
>>> FreeBSD implementation somehow.
>> That's interesting, but I'm afraid I don't know FreeBSD well
>> enough to help here. This does imply the problem isn't Samba
>> specific though (unless it's a complex interaction between
>> Samba+FreeBSD).
>
>
On my debian jessie server with zfs these settings seem to work.

max xmit = 65536
socket options = TCP_NODELAY

Copying an file from server to a windows 7 client increases from 50% to 
80% network utilisation on an  1GB link without jumbo frames when i add 
these settings.