On Aug 11, 2013, at 7:41 AM, Michael Ströder <[email protected]> wrote:
> Quanah Gibson-Mount wrote: >> On Aug 10, 2013, at 12:01 PM, Quanah Gibson-Mount <[email protected]> wrote: >>> On Aug 10, 2013, at 11:08 AM, Michael Ströder <[email protected]> wrote: >>>> Christian Kratzer wrote: >>>>> On Sat, 10 Aug 2013, Michael Ströder wrote: >>>>>> 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. >>>> >>>> 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 >>>> particular server. >>>> >>>> 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 >>>> though... >>>> >>>> => will try to play with this (I don't need a high write rate on those >>>> systems). >>> >>> I always set the syncprov checkpoint on all servers, replicas or masters. >> >> Correction. I load slapo-syncprov on all replicated db backends. I don't set >> the checkpoint. > > As said this is a MMR setup > => slapo-syncprov is loaded on all replicated DB backends > > Anythings else why contextCSN is not updated? > > Ciao, Michael. Doesn't happen to me with delta-syncrepl based MMR. --Quanah
