samba - Nov 2017 - Samba 4.7.1 - ldap multi process - excessive processes

Hi,

with the change in Samba 4.7 that ldap is now running multiple processes 
I'm having resource constraint issues.

Before it was fine to run any number of clients against samba, but now 
the ldap clients are limited.

My server quickly ran out of memory!

1) Is there any solution exept adding more RAM?
2) One process should be able to handle more than 1 connection! This is 
an archaic server side model ....

Actually the same issue also happens with the RPC Server which under 
certain conditions was started up to 50 000 times on 4.5 (not sure that 
is fixed).

BR
Thomas

Hi,

It's a known issue, where the extent of memory accumulation for 
processes wasn't understood (large chunks of memory, which tend to fail 
to be shared) until just after the release froze. There are patches 
upstream to implement a prefork process model (with a fixed number of 
waiting processes) and should be available in 4.8. In saying that, some 
considerations could be made for backporting. One alternative is that it 
might be possible for you to use single process mode (-M single) for now.

The prefork process model should apply similarly to the RPC server.

Cheers,

Garming


On 08/11/17 23:16, Thomas Rosenstein via samba wrote:
> Hi,
>
> with the change in Samba 4.7 that ldap is now running multiple 
> processes I'm having resource constraint issues.
>
> Before it was fine to run any number of clients against samba, but now 
> the ldap clients are limited.
>
> My server quickly ran out of memory!
>
> 1) Is there any solution exept adding more RAM?
> 2) One process should be able to handle more than 1 connection! This 
> is an archaic server side model ....
>
> Actually the same issue also happens with the RPC Server which under 
> certain conditions was started up to 50 000 times on 4.5 (not sure 
> that is fixed).
>
> BR
> Thomas
>

G'day Garming,
> It's a known issue, where the extent of memory accumulation for
> processes wasn't understood (large chunks of memory, which tend to
> fail to be shared) until just after the release froze. There are
> patches upstream to implement a prefork process model (with a fixed
> number of waiting processes) and should be available in 4.8. In
> saying that, some considerations could be made for backporting. One
> alternative is that it might be possible for you to use single
> process mode (-M single) for now.
>
> The prefork process model should apply similarly to the RPC server.
Indeed, we also had issues with rpc_servers eating all the 3GB memory of
a DC for just 150 users... Adding the -M single flag did fix the memory
gobbling issue. Actually we progressively added the -M single to a dozen
of domain we had already upgraded to 4.7.1.

Do you know if there are any drawbacks to using the -M single flag? I
noticed the number of samba processes is lower than with a samba 4.6
with this flag.

If you have a fix, I think it might be a good thing to backport this 
one, or at least change the default process model while waiting for the 4.8.

Cheers,

Denis
>
>
> On 08/11/17 23:16, Thomas Rosenstein via samba wrote:
>> Hi,
>>
>> with the change in Samba 4.7 that ldap is now running multiple
>> processes I'm having resource constraint issues.
>>
>> Before it was fine to run any number of clients against samba, but
>> now the ldap clients are limited.
>>
>> My server quickly ran out of memory!
>>
>> 1) Is there any solution exept adding more RAM? 2) One process
>> should be able to handle more than 1 connection! This is an archaic
>> server side model ....
>>
>> Actually the same issue also happens with the RPC Server which
>> under certain conditions was started up to 50 000 times on 4.5 (not
>> sure that is fixed).
>>
>> BR Thomas
>>
>
>
-- 
Denis Cardon
Tranquil IT Systems
Les Espaces Jules Verne, bâtiment A
12 avenue Jules Verne
44230 Saint Sébastien sur Loire
tel : +33 (0) 2.40.97.57.55
http://www.tranquil-it-systems.fr