[Samba] extremely low performance on Samba 4.2.14-Debian

L.P.H. van Belle belle at bazuin.nl
Wed Aug 16 21:21:34 UTC 2017

Hai Emmanuel, 

But ive re-read the complete thread.
Its strange that the old machine is so much faster.
In thinging a bit, and it can go two ways.. 
I'm trowing in things i get in my head based on experiance aka wild guesses, but review it i suggest.

Samba bug/problem in settings combinations ( or wait for multi threaded samba 4.7. and test that)

Hardware/linux (driver/setting) combination, i'll come to that later on.. 

For samba. 
Can try with the following to see if one of these is slowing things down. 
In thinking in (kernel higher = better cifs (smb protocol support), and maybe improvements in xfs support (i haven't checked that). 
And check with modinfo the nic driver. 
I want to know if it possible to see the (by samba) detected interface speed. ( and mtu/tcp size rwin ).

Smb.conf suggestions, and test order.
server signing = auto
Then again add:
ntlm auth = no
And im questioning these 2. 
In global you set. 
restrict anonymous 2

In the share.
guest ok = no

The google translater makes crap off:  This parameter nullifies the benefits of setting restrict anonymous = 2  :-/ 
Are these to settings conflicting or not.. In not sure here.

>From man smb.conf 
      guest ok (S)

           If this parameter is yes for a service, then no password is required to connect to the service. Privileges will be those of the guest account.
           This parameter nullifies the benefits of setting restrict anonymous = 2
           See the section below on security for more information about this option.
           Default: guest ok = no

About the hardware/linux. 

Did you install/setup the hardware, (not judging your knowlidge, my thoughts)
When you installed it, did you check the pci-e bus and the irq relations in the bios.
It is possible, the 40G nic is shareing the bus with the raid 6 contoller. 
That can slow down things. 
Bios raid/hdds/mainboard up to date, so changelog review cant harm. 
Is the nic using firmware? 
The output of : 

> -----Oorspronkelijk bericht-----
> Van: samba [mailto:samba-bounces at lists.samba.org] Namens 
> Emmanuel Florac via samba
> Verzonden: woensdag 16 augustus 2017 22:00
> Aan: Emmanuel Florac via samba
> Onderwerp: Re: [Samba] extremely low performance on Samba 
> 4.2.14-Debian
> Le Wed, 16 Aug 2017 21:55:05 +0200
> Emmanuel Florac via samba <samba at lists.samba.org> écrivait:
> > > 
> > > Samba is a rapidly changing program, a new minor version 
> is released 
> > > every 6 months (approx) and the changes are significant.
> > > 
> > > 4.7.0 is due out at in September and there are going to 
> be a lot of 
> > > improvements in it.
> > 
> > I've upgraded to 4.5.12 : absolutely no difference. smbd 
> consumes 100% 
> > of CPU when writing or reading a paltry 100 MB/s. I'll try 
> 4.6.x but 
> > I'm desperate. I'll probably need to replace the server altogether 
> > (and it's a PITA because it's 600 km away).
> And here we go: 4.6.7 isn't any better. Unfortunately I'm out 
> of ideas and out of resources, I'll switch servers for  an 
> old, faithful, obsolete Opteron-based one.
> --
> --------------------------------------------------------------
> ----------
> Emmanuel Florac     |   Direction technique
>                     |   Intellique
>                     |	<eflorac at intellique.com>
>                     |   +33 1 78 94 84 02
> --------------------------------------------------------------
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