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Re: syncrepl issue



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Dear Howard and list users,

Dans sa grande sagesse, Howard Chu a écrit, le 30.03.2009 22:46 :
> Oliver Henriot wrote:
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>> Dear list users,
>>
>> I have a master openldap 2.3 server which is replicated via syncrepl on
>> half a dozen other servers (2.3 too).
>> Due to a legacy application from which I have to import passwords once a
>> day, the master server is stopped, erased and re-built from scratch once
>> every day...
>>
>> I have noticed that all the replicas have recovered only a partial
>> subset of the entries and the strange thing is that all the replicas
>> have the same subset. They are all missing a few hundred entries.
>>
>> When I stop the replicas, erase their data and start them anew, they
>> replicate just fine and are consistent with the master server.
>>
>> I was wondering : could this be due to the fact that the replicas have
>> problems erasing the old entries and replacing them with the new set of
>> entries?
> 
> No.

OK

> 
>> Would increasing syncprov-checkpoint<ops>  and
>> syncprov-sessionlog<size>  values improve the situation?
> 
> No.

OK

> 
>> I also recall
>> reading something about a specific configuration directive to improve
>> delete replication but I have a feeling it was 2.4 specific...
> 
> What you're doing is unsupported. Syncrepl only works if all of the
> changes to the database are visible to the consumers, so that the before
> and after state can be determined. When you completely delete the
> provider DB and re-import it while the provider is shutdown there's no
> way for the consumers to track this, and after the delete there's no
> longer any record of the old contents on the provider.
> 
> If you're going to completely delete your database on the provider and
> expect the consumers to notice this, you must start the provider with an
> empty database so the consumers see the empty state and empty themselves
> accordingly. Then re-populate the provider and the consumers will
> likewise. All in all this is not a good way to operate your database...


Yes, I agree it's not good. Once I'll have got rid of the old system, I
won't have to do this any more.

I had envisaged doing an ldapdelete of all entries on the master before
shutting it down, but if just starting it up empty before importing the
data will suffice, that will be just fine until the old system is removed.

Thank you very much for your help.

Best regards,
- --
Oliver Henriot B.Sc. Ph.D. | Technicien de Maintenance
Moyens Informatiques et Multimédia | UMS MI2S | http://mi2s.imag.fr/
Domaine universitaire BP53 | 38041 Grenoble cedex 9 | France
tel.: +33 4 76 51 43 48 | fax: +33 4 76 51 47 15


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