1c (accounting application) and samba 3.0.24: huge perfs problems

Matthieu Patou mat+Informatique.Samba at matws.net
Sat Dec 6 11:00:04 GMT 2008


On 12/06/2008 01:05 PM, Volker Lendecke wrote:
> On Sat, Dec 06, 2008 at 12:25:15PM +0300, Matthieu Patou wrote:
>    
>>> Is this an appication accessed by one client ? Oplocks would help
>>> here if so (allowing the client to check locks locally and not
>>> have to go over the network).
>>>
>>>        
>> No it's a multiple client access but not everybody use it and of course
>> not every time, but the application must have been designed for using
>> oplocks or even if it is not the case this application could take
>> advantage of oplocks ?
>>      
>
> The application can not ask for oplocks, this is the client
> OS'es task. Oplocks are broken though when the second client
> opens the file. I've had a customer where the application
> (a MS Access based one) was slowed down by more than a
> factor of 10 when two people opened it vs only single
> access. The customer told me Samba would be slow because on
> Windows it was fast. Certainly against Windows they only
> tested single user access. Guess what happened when a second
> client opened the application when it was stored on
> Windows...
>
> Summary: Multi-User file base DB access is broken by design
> if done over a network :-)
>    
Yeah I know and I already warned people in my office about that and 
about the fact that we should move to new version that propose a real 
client/server (with a real database).
Can you still confirm that I have the big picture correct:
* When an application is using oplock it shouldn't issue lock request 
over the network
* When using write oplock , if a second client just open the same file 
the server will issue an information that the first client should 
discard its locks
* When using read oplock , if a second client just open the same file 
the server will not issue that information

If you could be kind enough I attached an extract of the message pattern 
I have between my samba server and the computer, can you have a look on it.
And even if I know that this db file or fileserver is not the best 
design I wonder if I could change some parameters on the samba server 
for this application to be a bit more responsive.


Matthieu.


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