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Re: how to configure multi-master

On Sat, Jul 19, 2008 at 11:19 AM, Dieter Kluenter <dieter@dkluenter.de> wrote:

"Liutauras Adomaitis" <liutauras.adomaitis@gmail.com> writes:

> Hello,
> I feel a little bit spaming this list, but still - how to setup multi-master?
> Reading
> http://www.zytrax.com/books/ldap/ch7/#ol-syncrepl
> http://www.openldap.org/doc/admin24/replication.html
> gave me impression that simply adding serverID in global (above database)
> section, syncrepl and overlay syncprov in database section should give me
> multi master setup. THis did worked - meaning I got the same data on both
> servers, but I couldn't make updates to either of servers. Google says
> absolutely nothing about that. The error is "shadow context; no update
> referral at ..." Adding updateref directive to conf file seemed to me wrong,
> because multi master is meant to be multi write nodes setup, so I didn't tried
> that. After about four hours of searching for any full working example of
> multi-master implementation I decided to put mirror mode true on both servers
> at the end of conf file - that did the trick.
> So do I need add mirror mode or not? It is not clear the difference of
> multi-master and mirror mode, which I asked on different message.
> I didn't tried setting mirror mode false and see if updates are working, but
> if this is what I missed, then it is very strange, that official
> administrators guide is missing such a key point.

Multi-way replication and mirror mode are two different
aproaches. While ldap servers configured for n-way replication are
all visible and available by all clients and all allowing all
operations. Mirror mode is a sort of backup and standby system. Only
one ldap server should be visible and available, thus allowing write
operations, while the second ldap-server is in hot standby position,
and only available to clients if the first server fails.
Run test050 to get simple configuration examples for n-way
replication. For mirror mode configuration see
http://www.openldap.org/doc/admin24/replication.html, part 17.3.2 and

Your explanation has answered the other my question "difference between multi master and mirror mode".

I was always using Mandriva rpms and never compiled openldap by myself. But few days ago I did compiling of openldap srpm and saw it doing some tests. I'm going to dig arround for how to make this test050 on Mandriva.

Thanks a lot