s4 ldb tdb limits

Oliver Liebel oliver at itc.li
Thu Aug 27 14:54:17 UTC 2015

As i wrote earlier to this list and to Jakub,
this is not an  emergency / Rescue Job.  No existing  S4 Environment.
Customers with (big) existing MS-AD, who would like to switch to S4.
Extensive Pre-Testing is possible and necessary.

Am 27.08.2015 um 16:23 schrieb Jakub Hrozek:
> (Top posting; travelling with only mobile)
> As I wrote to oliver earlier while I think using lmdb as ldb back end is eventually a good idea it should be done together with refactoring the tdb back end and should not be done in haste. There is also no guarantee it would help the particular customer..
> For problems with existing environments Matthieu's unpack patches (he also had some other about reallocs..) or maybe even using the nosync ldb option might be less risky..
> On Aug 27, 2015 12:31 PM, Nadezhda Ivanova <nivanova at samba.org> wrote:
>> Hi Oliver,
>> I don't think I can be particularly helpful in this matter - the scope
>> and goal of our project is quite different - we seek to replace the
>> Samba LDAP service with OpenLDAP, rather than just write a new ldb
>> backend. If Jakub or you have any specific questions, I'll see if I can
>> be of assistance.
>> Best Regards,
>> Nadya
>> On 08/27/2015 03:23 PM, Oliver Liebel wrote:
>>> Am 27.08.2015 um 00:21 schrieb Oliver Liebel:
>>>> Am 26.08.2015 um 18:02 schrieb Jeremy Allison:
>>>>> On Wed, Aug 26, 2015 at 03:46:41PM +0200, Oliver Liebel wrote:
>>>>>> Am 26.08.2015 um 04:34 schrieb Andrew Bartlett:
>>>>>>> On Tue, 2015-08-25 at 09:34 -0700, Jeremy Allison wrote:
>>>>>>>> Yeah, lmdb and backending with OpenLDAP is our
>>>>>>>> long term solution for these limits I think.
>>>>>>>> Nadia, any progress report on migrating us over ?
>>>>>>> Jeremy,
>>>>>>> I should caution you that while moving to lmdb rather than tdb may be
>>>>>>> reasonably practical (a prototype has been developed so far), the
>>>>>>> task
>>>>>>> of moving to using OpenLDAP is I feel an order of magnitude larger
>>>>>>> than
>>>>>>> the task to move us to using MIT Kerberos.  Equally, when finished it
>>>>>>> promises great improvements, but we should be very clear that it
>>>>>>> needs
>>>>>>> commensurate resources.
>>>>>>> The issue is this:
>>>>>>> At it's heart, Samba4 turned out to be a series of RPC services
>>>>>>> clustered around the LDB module stack.  The vast majority of the
>>>>>>> complexity is in that stack.   As I understand it, the OpenLDAP
>>>>>>> backend
>>>>>>> project seeks to 'simply' replace that stack, using a number of Samba
>>>>>>> libraries in the process.
>>>>>>> I hope this helps give an idea of the scale involved here.
>>>>>>> Thanks,
>>>>>>> Andrew Bartlett
>>>>>> I fully agree with Andrew.
>>>>>>    From my point of view (and that of many customers) there are at
>>>>>> this point
>>>>>> 2 major tasks to get S4 into larger/enterprise scale:
>>>>>> - Fast (LM)DB Backend
>>>>>> - W2K12 DC compatibility
>>>>>> I know for sure how big the task is, to get OpenLDAP as an
>>>>>> S4 Backend with full Schema Semantics and DRSUAPI or any kind of DRS
>>>>>> working, as Andrew and I already worked a few years ago on the
>>>>>> S4/OpenLDAP Backend.
>>>>>> And i would love to see OpenLDAP as an S4 Backend, but from a
>>>>>> realistic point of
>>>>>> view, this task can't be finished very shortly, because its really
>>>>>> complex.
>>>>>> I think in the meantime it is the best approache,
>>>>>> to get the LDB/TDB Stack enhanced / replaced with LMDB,
>>>>>> so that large(r) scale Installations could be satisfied.
>>>>>> We should get ' the best Database under the hood ' working. The
>>>>>> quicker, the better.
>>>>>> One side effect: When the S4/OpenLDAP Job is done, we got already a
>>>>>> mostly
>>>>>> compatible LMDB-Backend inside S4 working.
>>>>>> @Andrew, Nadezhda and Jakub:
>>>>>> could you please submitt  a full description / explanation of the
>>>>>> minor tasks
>>>>>> to get TDB replaced with LMDB.
>>>>>> I will try to get some hr, to get this done (but no promises,
>>>>>> i'll keep you informed)
>>>>> Yeah, I wasn't saying it was going to be easy :-).
>>>>> That's why I ust asked Nadia for a status update,
>>>>> nothing more :-).
>>>> Jakub pinged me, in the next days
>>>> he'll bring me up to date about the oustanding
>>>> tasks regarding TDB / LMDB  Replacement.
>>> Update:
>>>    It looks like i could get shortly 2 Workers/Coders for the TDB <->
>>> LMDB Replacement Task
>>> to support Jakub.
>>> @ Nadehzda: Maybe some additional Advices / Hints / Whatever...
>>> regarding LMDB Integration
>>> from Symas could be helpful  - if possible.
>>> Thanks in Advance
>>> Oliver

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