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Re: n-way replication question

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 KlÃnter | Systemberatung
sip: +49.180.1555.7770535