OpenLDAP and Samba4

Matthieu Patou mat at
Sat Apr 20 14:34:51 MDT 2013

On 04/20/2013 11:28 AM, Howard Chu wrote:
>> Date: Sat, 20 Apr 2013 16:04:46 +0200
>> From: G?mes G?za <geza at>
>> 2013-04-20 12:17 keltez?ssel, Luke Howard ?rta:
>>> > On 20/04/2013, at 7:32 AM, G?mes G?za <geza at> wrote:
>>> >
>>>>>> Sorry to express my own opinion as not a samba team member or
>>>>>> regular
> developer (few small patches doesn't count), but instead of trying to use
> OpenLDAP as a backend for samba, wouldn't be useful to try to use 
> tdb/ldb as
> the backend for OpenLDAP and to see what other changes are needed in 
> order to
> have it listen on 389/tcp and 636/tcp on behalf of Samba, something 
> like the
> s3fs setup?
>>>> That's not a bad idea: enforce the ?business logic? (i.e. SAM
> constraints, etc) in the actual backend database itself, rather than 
> in the
> layer between the protocol and the backend database. (We did something
> similar, but much simpler, with the NetInfo backend for OpenLDAP some 
> years ago.)
>>>> However: Howard and the OpenLDAP team have invested a lot in backend
> database design (see back-mdb) and I would expect they'd like to leverage
> this, not just the protocol front-end.
>>> >
>>> > -- Luke
>> Switch from tdb to mdb perhaps?
> (mdb is now called LMDB, to avoid confusion with Microsoft Access mdb 
> etc.)
> This has been discussed privately. It is unfortunately not a slam dunk 
> today due to concerns about 32 bit compatibility. Since LMDB works by 
> directly referencing data thru a memory map, it can't manage more than 
> ~2GB on a 32 bit machine. This has not been a concern to us in 
> OpenLDAP because most server deployments are on 64 bit hardware these 
> days. The notable exception, smartphones, rarely have databases bigger 
> than a few MB in size.
> We recognize that LMDB may not be practical for some 32 bit embedded 
> servers that Samba targets. We anticipate that 64 bit ARM will replace 
> these devices soon and the problem 
I'm not sure a lot of persons targets AD DC on 32 bit systems, still 2G 
database means hundreds of users so it could be still meaningful for 
small appliances using 32 bit ARM.


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