Replication rolling back to normal.

Started by Dasitha Karunajeewaover 9 years ago3 messagesgeneral
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#1Dasitha Karunajeewa
dasitha@duosoftware.com

Dear Team,

I have installed PostgreSQL 9.6 on two servers. One is master and other is
for slave server. Current setup as follows.

- Master Server - pgmaster
- Salve Server - pgslave

To implement this I have followed this article
https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-on-postgresql-on-an-ubuntu-12-04-vps

Master Slave combination is working fine.

when I create a file at the file trigger location ex:
/tmp/postgresql.trigger.5432 on *pgslave *server, it started accepting read
and as well as write request which is perfectly correct.

What I want to know is how to switch them back to the normal status. That
means pgmaster need to be the Master server which acept the writed and
pgslave that accepts only reads along with the replication.

Regards,

Dasitha.

#2Michael Paquier
michael@paquier.xyz
In reply to: Dasitha Karunajeewa (#1)
Re: Replication rolling back to normal.

On Fri, Oct 21, 2016 at 10:10 PM, Dasitha Karunajeewa
<dasitha@duosoftware.com> wrote:

What I want to know is how to switch them back to the normal status. That
means pgmaster need to be the Master server which acept the writed and
pgslave that accepts only reads along with the replication.

If your promoted standby got ahead of the former master, you could use
the promoted standby as a new master, and replug the former master as
a standby. The latter step can be done by either running pg_rewind on
the former masfer or taking a new base backup from the promoted
standby and use that to set up a new standby. pg_rewind will be
successful to run only if the master has kept WAL segments from the
last checkpoint record where WAL forked when standby has been
promoted.
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Michael

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#3Michael Paquier
michael@paquier.xyz
In reply to: Dasitha Karunajeewa (#1)
Re: Replication rolling back to normal.

On Mon, Oct 24, 2016 at 2:20 PM, Dasitha Karunajeewa
<dasitha@duosoftware.com> wrote:

Hi Michael,

Thanks a lot for the information. I am totally new to Postgres clustering. I
have follow up the below-attached article.
https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-on-postgresql-on-an-ubuntu-12-04-vps

Can u guide me on how to do it as u mentioned :)

Documentation is your best friend:
https://www.postgresql.org/docs/9.6/static/high-availability.html
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Michael

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