[Samba] aio settings for samba 4.3

Russell R Poyner russell.poyner at wisc.edu
Thu Jul 21 18:56:19 UTC 2016


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).




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