Christian Kratzer wrote:
On Sat, 10 Aug 2013, Michael Ströder wrote:
> Are contextCSN values on all replicas really in sync if changes were correctly
> 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
Thanks for following-up.
AFAICS the above directive specifys when to write the contextCSN to the DB on
disk similar to checkpoint directives for DB backends. So in case of a server
crashing you have a quite recent contextCSN with the server-id of this
But since all replicas are up and running and I query the contextCSN values
via LDAP I presume this is not relevant for my problem. Well, one never knows
=> will try to play with this (I don't need a high write rate on those systems).