Re: High Availability / Replication with Sequoia

Mr(dot)Frog(dot)to(dot)you(at)googlemail(dot)com wrote:
> Hi Guys,
>
> I have been testing / working with Postgres for a work project, and so
> far I am really impressed with this DB system. Takes a little getting
> used to, but I am really beginning to love it.

Good to hear it Mr ...Umm... Frog.

> I am looking now at a scenario that does not seem to be a native
> ability of Postgres, but might possibly be overcome with Sequoia. I am
> hoping that there exists the possibility of using Sequoia to replicate
> a DB between / among a number of machines in the office, some of which
> are not always connected to the lan.

You might want to look at slony with log-shipping
http://www.slony.info/documentation/logshipping.html
Have a master server on the lan, others grab files as and when they
need. Do read the "limitations" though.

> The application does not allow writeback to the db, so for all intents
> and purposes you can consider it read only.

Fine with slony.

> To keep the applications database up to date with new information I
> would be using ETL applications like Spoon / PDI. This will be done to
> an as yet undecided 'point of origin', but it is probably safe to say
> that it will be a commercial db server somewhere on our network. The
> latency from our network to the 'Data Warehouse' (read as badly
> managed dogs breakfast) is huge. Suffice to say the desire for local
> db's is high, as is the desire to make the application portable for
> our sometimes connected laptop users.

The syncing with your commercial DB is probably the most fiddly bit.
That's not so bad, since it's one-way.

> Does anyone have any experience or comments that they would like to
> share about this sort of scenario? Its a fairly big jump from just
> having Postgres running on my laptop for dev purposes to pushing this
> to multiple machines and I would really appreciate any feedback you
> guys might have.

Not used the log-shipping variant of slony, but I'm happy enough with
the regular connected-version.

--
Richard Huxton
Archonet Ltd