> After one hole day of testing :)
>
> The single master -> single slave was ok.
>
> But, what I need to implement is this.
>
> I have 15 databases at 15 points, all connected to internet, and
> interconected using openvpn.
>
> Each point of sale have its own database different from each other, this
> was tougth from design, that it could be easier to replicate N
> differents database than N diferent tables.
>
> What I need, is to replicate, all 15 databases to a single server, in
> that way, I can consolidate all information.

You realize, I trust, that this will mean that the "consolidation server"
will have 15 slaves, and that none of them can be modified...

There are multiple ways of doing this, of course.  If each POS unit has
its own distinct namespace/schema (a GOOD idea), or if the tables differ
for each instance (probably not so good...) then you could conceivably fit
them all into a single database backend and cluster.  That would provide
the easiest consolidation of data, which has plenty of merit.

Having 15 databases on one cluster (e.g. - one postmaster) or 15
postmasters with a database apiece would be the other two obvious options.
 They would leave the Slony-I instances more independent of one another;
it's probably less suitable for your purposes...

> My concern is about the use of slon.. since I need slon running at the
> master and slave, I belive, that only once instance of slon must existis
> per box... so, how do I setup 15 slon at the slave box?

You'd probably want to run a script that invokes 15 slon instances with
the varying parameters.

We have one box where we run 12 slon instances, and that's just what we
do.  Each is configured to point to a different log directory, and a
different database instance, which is just no problem at all.

> P.D. Do you have an irc channel?

Yes.  Look on irc.freenode.net for the "slony" channel.