Re: Understanding Synchronization Problem using syncrepl

[Sam Tran <stlist@gmail.com>]

On Mon, Dec 28, 2009 at 12:39 PM, Andrea Cirulli <acirulli@gmail.com> wrote:
> Hi Sam,
> we are using syncrepl mechanism, and we don't decide yet if the consumer
> will point to a specific IP ( let's say half of consumer on multimaster1 and
> the rest on multimaster 2) or pointing to Virtual IP of a RADWARE that is in
> charge of balancing ( only failover not load balancing).
> In any case, I have to implent or found a solution more general as possible,
> in order to handle the two scenarios.
> If you have any suggestion or something already implemented I will
> appreciate your help.

We have decided to point the consumers to a virtual IP fronting the
pair of providers for LDAP replication.
In my tests where I manually fail over from one provider to the other,
syncrepl in refreshAndPersist mode works with no problem.
Delta-syncrepl most of the time works. But I had instances where
replication was lagging; the consumer manages to contact the active
provider, but queries to the accesslog database return no entry when
an ldapsearch with the same filter on the command line returns more
than one entry. Eventually the consumer would resync again.

I am updating my python script that checks whether a given consumer is
in sync with the provider. Once I am done I can share it with you if
you wish. Buchan wrote a Perl script that does something similar and
works with Nagios:
http://www.zarb.org/~bgmilne/hobbit/bb-openldap.pl

--
Sam