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some questions on n-way replication



Hello,
there are some examples of n-way replication configuration examples
around and I would like to ask for some authoritative configuration
advice. 
test050 for example gives the impression that serverID parameter has
to be multivalued at each configuration file, i.e. in a 3-way
replication: 

serverID 1 $URL1
serverID 2 $URL2
serverID 3 $URL3

same applies to replication ID, it seems that sid and rid have some
mutual relation, and all participating hosts should be aware of all
rids, i.e. in a 3-way replication:

syncrepl rid 1 provider=$URL1
syncrepl rid 2 provider=$URL2
syncrepl rid 3 provider=$URL3

mirrormode true
overlay syncprov
syncprov-reloadhint true
syncprov-checkpoint 1 5

with this configuration each host has to connect to itself and to all
participating hosts. 
I have done some extensive testing in the last few days and found that
a system configuration as described above caused contextCSN to be set
to sid 000 and led to a quite unstable system. The following
configuration provided correct contextCSN setting and a stable system:

serverID 1
syncrepl rid 1 provider=$URL2
syncrepl rid 3 provider=$URL3
mirrormode true
overlay syncprov

serverID 2
syncrepl rid 2 provider=$URL1
syncrepl rid 3 provider=$URL3
mirrormode true
overlay syncprov

serverID 3
syncrepl rid 3 provider=$URL1
syncrepl rid 1 provider=$URL2
mirrormode true
overlay syncprov
 
My question now is: is this a proper way to setup n-way replication or
is this a wrong, but working, configuration.

-Dieter

-- 
Dieter KlÃnter | Systemberatung
http://www.dpunkt.de/buecher/2104.html
sip: +49.180.1555.7770535
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