[Samba] SMB2 write performace slower than SMB1 in 10Gb network

Zhiming Zhou iscsi at yahoo.cn
Wed May 2 02:06:15 MDT 2012

于 2012/4/28 14:58, Volker Lendecke 写道:
> On Sat, Apr 28, 2012 at 01:46:35PM +0800, Zhiming Zhou wrote:
>> I use Iometer to test normal file read/write performance,
>> at first, SMB2 is not enabled,test 1MB sequential read/write performance
>> with SMB1, I got 610 MB/s write performance which
>> is really good, while read performance is just 280 MB/s.
>> Then I change "max protocol" to "SMB2" in smb.conf to enable
>> SMB2, other configs in smb.conf are not changed, restart samba,
>> reconnect in Windows 2008, use Iometer to run test again, I got
>>   470 MB/s write performance and 505 MB/s read performance.
>> It's quite good that read performance bursts with SMB2, but
>> write performace droped by 140 MB/s, I run this write test
>> serveral times again, write performance indeed droped a lot,
>> so is it normal that SMB2 write performance is slower than
>> SMB1?
> No, this is not normal. Maybe you want to enable async I/O.
> Depending on the platform, plain aio might work with
> aio write size = 1
> It might be a good idea to also enable
> vfs objects = aio_fork
> With latest Samba Jeremy Allison has also added the
> aio_pthread module, but that is not yet in released code.
> You can get it from the latest v3-6-test branch in our git
> repository.
> With best regards,
> Volker Lendecke

Tested SMB2 write peformance again under 10Gb network with AIO enabled, 
I set

aio write size = 1

and got 332.17 MB/s output, which is slower than previous 470 MB/s (AIO 
enable aio_fork vfs object, test result is almost the same.

In my opinion, SMB2 write should be faster than SMB1 even when AIO is 
isn't it?


Uranus Zhou

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