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Re: contextCSN values and MMR

Quanah Gibson-Mount wrote:
> On Aug 10, 2013, at 12:01 PM, Quanah Gibson-Mount <quanah@zimbra.com> wrote:
>> On Aug 10, 2013, at 11:08 AM, Michael StrÃder <michael@stroeder.com> wrote:
>>> Christian Kratzer wrote:
>>>> On Sat, 10 Aug 2013, Michael StrÃder 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.

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