Ulrich Windl wrote:
Christian Kratzer ck-lists@cksoft.de schrieb am 10.08.2013 um 19:43 in
Nachricht alpine.BSF.2.00.1308101942120.18017@pohjola.cksoft.de:
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 contextCSNto 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.
do you "query" by slapcat or by an LDAP search? For the former it's documented that contextCSN is updated lazily. For the latter I'm not sure.
Using slapcat in a monitoring check invoked every minute would be pretty dumb. So of course I'm retrieving the contextCSN values from replicated DBs via LDAP.
Ciao, Michael.