Re: contextCSN values and MMR

[Christian Kratzer <ck-lists@cksoft.de>]

Hi,

On Sat, 10 Aug 2013, Michael StrÃder wrote:

> HI!
>
> Are contextCSN values on all replicas really in sync if changes were correctly
> replicated?
>
> I've implemented a monitoring check used with normal MMR setup (OpenLDAP
> 2.4.35, own build on Debian Squeeze) which also checks the contextCSN values
> on all replicas compared by server-id.
>
> Sometimes we observe, even in isolated tests, that contextCSN values for a
> certain server-id differ for quite a while (up to hours) even though the
> changes coming from that server were definitely replicated to all other
> replicas. After a while the contextCSN values get suddenly updated.
> Unfortunately this does not always happen.
>
> Any hint is highly appreciated.

I have always suspected that this is due to the specific setting of:

       syncprov-checkpoint <ops> <minutes>
              After a write operation has succeeded, write the contextCSN to the underlying database  if  <ops>  write
              operations  or more than <minutes> time have passed since the last checkpoint. Checkpointing is disabled
              by default.

Not sure though.


Greetings
Christian


> Ciao, Michael.

--
Christian Kratzer                      CK Software GmbH
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