Re: n-way replication question

[Gavin Henry <ghenry@OpenLDAP.org>]

Dieter Kluenter wrote:
> Gavin Henry <ghenry@OpenLDAP.org> writes:
>
> > Dieter Kluenter wrote:
> > > Holger Kaelberer <Holger.Kaelberer@telefonica.de> writes:
> > >
> > > > Hi,
> > > >
> > > > Dieter Kluenter wrote:
> > > >
> > > > > > What is your configuration on all servers?  In detail, what's the
> > > > > > value of the serverID statements, of the syncrepl statements and
> > > > > > what's the URI you're running them with?
> > > > > Solved it, silly me!
> > > > > The initial slapd.conf should only contain one serverID statement
> > > > > without any additional address, only after starting all peers the
> > > > > serverID has to be modified to include all participating peers.
> > > > seems that I had exactly the same problem when setting up
> > > > multimaster-repl. By trial and error I solved it by only defining one
> > > > serverID on each host:
> > > >
> > > > # master1
> > > > serverID 1
> > > >
> > > > # master2
> > > > serverID 2
> > > >
> > > > With this setting multimaster-repl seems to work correctly.
> > > >
> > > > As I don't understand exactly how this statement affects
> > > > multimaster-replication my question is, whether it is ok to do so or
> > > > do I *need* to define all serverID as
> > > >
> > > > serverID NUM URL
> > > >
> > > > on all participating master.
> > > If one thinks about it, it is obvious that each participating peer
> > > has
> > > to be informed about its sid, as other peers are not participating
> > > prior to the initial setup, its only one sid.
> > > After starting all peers, they have to be informed about all
> > > particiating sids, that is prior to adding any data the sids have to
> > > be anounced. So my initial configuration was as you described above.
> > > After the initial setup I added all sids with a small shell script,
> > > copied from test050,
> > > $LDAPMODIFY -x -D cn=config -H $HOST -w $CPW <<EOF
> > > dn: cn=config
> > > changetype: modify
> > > replace: olcServerID
> > > olcServerID: 1 $URL1
> > > olcServerID: 2 $URL2
> > > EOF
> > > Now the contextCSN looks like
> > > contextCSN: 20081022192158.873555Z#000000#001#000000
> > > contextCSN: 20081022184543.202017Z#000000#002#000000
> > > note the different sids 001, 002. ContextCSN, that is time + sid,
> > > indicate which peer modified the database last.
> > > -Dieter
> > I pretty sure this is what test50 does at
> > http://www.openldap.org/doc/admin24/replication.html#N-Way%20Multi-Master
> >
> > When we add 1 $URL1 etc. it's after the server has already been
> > bootstrapped.
> >
> > I will rewrite this section. If using slapd.conf, would we need to add
> > this after slapd has been started and restart the masters then?
>
> If you use slapd.conf, at the initial setup of each peer, only a
> single 'serverID' without URI has to be configured, after the start of
> all particating peers, you modify cn=config to add the other serverID
> plus adding URI, if applicable. You don't have to restart any
> participating server.
>
> -Dieter

Obviously that's the way on the fly, but I meant for users who are still 
using slapd.conf and don't want to use cn=config (for whatever reasons).

--
Kind Regards,

Gavin Henry.
OpenLDAP Engineering Team.

E ghenry@OpenLDAP.org

Community developed LDAP software.

http://www.openldap.org/project/