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Re: multiple replication scenarios questions

Guillaume Rousse wrote:
> Hello list.
> 
> I had a look at section 18 of the admin manual, as I was trying to 
> figure difference between scenarios 18.2.2 (N-way multi-master) and 
> 18.2.3 (mirror mode). Whereas the descriptions of both scenarios are 
> quite clear, given examples configuration are quite confusing (at least 
> for me).
> 
> First, they are quite hard to compare, as the first one uses LDIF 
> syntax, whereas the second uses the classical file configuration syntax.
> 
> Second, they both use the same directives:
> - a different serverId for each nodes
> - mirrormode on for each nodes
> - syncrepl directives for each nodes
> 
> The only difference being than for multi-master, each node has syncrepl 
> directives for each nodes (including himself), whereas for mirrror mode, 
> each node only has syncrepl directives for other nodes. But it's hard to 
> figure if that's because of the replication scenario, or just because in 
> the first case, the configuration has to be identical everyhwere given 
> that it's replicated automatically.
> 
> So, what is supposed to be different at configuration level between 
> those two scenarios ?

http://www.openldap.org/lists/openldap-software/200910/msg00089.html

> Additonal question: doesn't a classical single-master + multiple slaves 
> scenarios, where each slave use chain overlay to automatically forward 
> all changes to the master, also achieve exactly what is described in the 
> mirror mode description ?

Without the mirrormode feature you won't get automatic failover and recovery
capabilities.

-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/