[pgpool-general: 2884] Re: pgpool active-active (multi-site) sync?

[Yugo Nagata]

Hi,

On Mon, 26 May 2014 19:35:14 +0300
Guy Meler <melguy at gmail.com> wrote:

> Hey! :)
> I couldn't find any documented solution for the scenario I have:
> I want two pgpool instances, one for each site, each of them serves
> different clients. (active-active)
> the pgpool in site B redirects writes query to the master in site A. (reads
> are on the same site)

I assume there are PostgreSQLs on both sites of A and B with
streaming-replication configuration, and the "master" means the primary DB. 
Is this right?

> What I wonder is, if the master in site A dropped, how the pgpool in site B
> will know that?
> In general, is there any possiblity to operate in active-active mode, with
> sync between them?

If both DBs on A and B are specified in backend_hostnameX at both pgpool,
each pgpool can detect failure, whichever DB fails. And, backend status
is shared between pgpools by using watchdog. You don't need to use Virtul IP.

> 
> Thank you very much!


-- 
Yugo Nagata <nagata at sraoss.co.jp>