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Re: WARNING: No dynamic config support for database ldbm

> Pierangelo Masarati schrieb:
>>>I'm trying to build an OpenLDAP (2.3.18) server and to make it run on an
>>>"embedded" mipsel/uclibc device running Linux.
>>>After some initial hardships, I was able to build slapd + libs + utils
>>>etc. successfully.
>>>However, when I run it (slapd -d 5), I can see a warning:
>>>WARNING: No dynamic config support for database ldbm
>> It's warning you that back-ldap does not support dynamic configuration
>> using back-config

^^^ Sorry, of course I meant back-ldbm

> Well, that's exactly what the warning says.
> But I don't understand why (I think I used the correct flags to build it
> with ldbm support).

It doesn't support that feature, there is nothing you can do (besides not
using it).  You built it fine, and I bet you configured it fine.  It's
just like that, there's nothing you can do other than submitting a patch
that implements that missing feature, and likely it won't be accepted
because back-ldbm will disappear from the next minor version of OpenLDAP.

>>>I was going to use ldbm, and to make the binaries as small as possible.
>> Poor choice, if you start from scratch (poor choice in any case).
> Anyway, I built it once again, and now use "ldif" database.
> At least it works (and the binary is smaller, too).

back-ldif is not intended for general usage, because of SEVERE performance
issues and likely missing features.

>> see above.  It's harmless, as soon as you do not intend to run-time
>> modify
>> the configuration of slapd.
> How can it be "not harmless", as I'm not able to add any data to the db
> (or fetch any existing data)?

That warning __IS__ harmless, I'm telling you, because it has nothing to
with the fact you haven't been able to make it work.  That warning is
going to appear as soon as you add the "database ldbm" line to slapd.conf,
so I don't see how you could use back-ldbm without noticing that warning.

>> As I'm not psychic I can only guess.  Sorry for asking silly questions;
>> did you load any data into slapd?
> First, I copied data from the other server (as I always do with new
> servers) - it didn't work.
> Then, I tried adding data with slapadd - still without success.

Do you mean slapadd failed or slapadd succeeded but subsequent operations
failed?  Does "cd tests ; make ldbm" lead to any errors?  If it doesn't,
then back-ldbm built just fine.  If there are any errors, please report
about them.

>> Did you load it as root and then ran
>> slapd as another user?
> So far, I've been running everything as root.
>> does "/etc/openldap/db/dn2id.dbb" exist?  does any
>> of the portions of that path exist?
> Yes, it exists, but for some reason it couldn't be opened - I guess
> because slapd can see the file(s), but can't read the data in it - as in
> this warning "no config support for ldbm".

Gee, please stop talking about that warning!

> Anyway, rebuilt OpenLDAP with really minimal options (I hope):
> ./configure --target=mipsel-linux --host=mipsel-linux
> --build=i386-pc-linux-gnu     --with-yielding_select=no --with-tls=no
> --with-cyrus-sasl=no --prefix=/usr --enable-slurpd=no --enable-ipv6=no
>     --sysconfdir=/etc --localstatedir=/var/run/ldap --enable-overlays=no
> --libexecdir=/usr/sbin --enable-bdb=no --enable-ldbm=no --enable-hdb=no
> --enable-monitor=no --enable-relay=no --enable-ldap=yes
> Now I use "ldif" database, I added data with slapadd and the server is
> running fine (and uses only about 2 MB of RAM), so I think I will not
> try ldbm again.
> Anything special I should know about the "ldif" database?

Yes.  From slapd-ldif(5):

  The  LDIF  backend  to  slapd(8) is a basic storage backend that stores
  entries in text files in LDIF format, and exploits  the  filesystem  to
  create  the tree structure of the database.  It is intended as a cheap,
  low performance easy to use backend, and it  is  exploited  by  higher-
  level internal structures to provide a permanent storage.

Unless you can live with that, don't use it.  Use back-bdb or back-hdb


Ing. Pierangelo Masarati
Responsabile Open Solution
OpenLDAP Core Team

SysNet s.n.c.
Via Dossi, 8 - 27100 Pavia - ITALIA
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Email:    pierangelo.masarati@sys-net.it