[Samba] aio settings for samba 4.3

[Achim Gottinger]

Am 21.07.2016 um 22:59 schrieb Jeremy Allison:
> On Thu, Jul 21, 2016 at 10:50:16PM +0200, Achim Gottinger wrote:
>>
>> 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.
> That's kind of voodoo I'm afraid. By default Samba sets
> TCP_NODELAY, and max xmit is only used on SMB1, and modern
> Samba and Windows 7 should only be using SMB2.
Thank you for the clarification, finaly gotta drop TCP_NODELAY from 
configs now.
Indeed the connection is using smb2_10. I assume some intermediate 
caching influenced the copy test.

Tested it a few times with these settings enabled/disabled before i 
posted but still...
Now im at 80% without these settings.

It is mentioned here (together with the abandonen IPTOS_LOWDELAY)
http://unicolet.blogspot.de/2013/03/a-not-so-short-guide-to-zfs-on-linux.html

I assume

zfs set xattr=sa tank/fish
zfs set atime=off tank/fish

are an good idea on freebsd as well.