Re: WAL and master multi-slave replication

At 19:05 24/06/2009, Alvaro Herrera wrote:
>Eduardo Morras wrote:
>
>Hi,
>
> > I'm currently building a Pg multiserver and have a question about the
> > possibility of working with WAL in a multislave environment.
> >
> > I have few master servers (write only) and multiple slave servers (read
> > only). I want to write the WAL files from masters in a central postgres
> > and that the multiple slaves reads them from time to time and auto
> > update.
>
>Never heard of a "multiserver". I assume you mean there's a bunch (zero
>or more) slaves for each master.

Yes, there will be 3 masters recolleting data
(doing updates, inserts and deletes) for now and
5 slaves where we will do the searches. The
slaves must have all the data recollected by the
3 masters and the system must be easily
upgradable, adding new masters and new slaves.

>there's a suite to handle this kind of thing using pg_standby, including
>cleanup of old logs; see
>https://projects.commandprompt.com/public/pitrtools

Didn't know about this solution (PITR yes, but not pitrtools) i'm checking it.

>Mind you, the WAL files are not stored in a database but in raw files.
>I have never seen anyone advocating the use of a database to store them.

Well, i was thinking in slaves servers doing
selects to the "central repository" to retrieve
the wals archives from timestamp to timestamp and processing them.

Thanks

--------------------------------
Eduardo Morrás González
Dept. I+D+i e-Crime Vigilancia Digital
S21sec Labs
Tlf: +34 902 222 521
Móvil: +34 555 555 555
www.s21sec.com, blog.s21sec.com

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