Re: PG Upgrade with hardlinks, when to start/stop master andreplicas - Mailing list pgsql-general

From Martín Fernández
Subject Re: PG Upgrade with hardlinks, when to start/stop master andreplicas
Date
Msg-id 5c6c2c3e3ec218380d000001@polymail.io
Whole thread Raw
In response to Re: PG Upgrade with hardlinks, when to start/stop master and replicas  (Hellmuth Vargas <hivs77@gmail.com>)
Responses Re: PG Upgrade with hardlinks, when to start/stop master and replicas  (Stephen Frost <sfrost@snowman.net>)
List pgsql-general
Stephen,

Thanks for information! I've refactor our migration scripts to follow the suggestions. 

One extra question that popped up. As long as we don't start the standby (after running rsync), we can always `rm -f $PGDATA_10` and promote the standby if necessary for failover right ? We also need to `mv` pg_control.old to pg_control in the old data directory.

Thanks!

Martín

On Tue, Feb 19th, 2019 at 12:39 PM, Hellmuth Vargas <hivs77@gmail.com> wrote:
Thank you Stephen 👍

El mar., 19 de feb. de 2019 a la(s) 10:05, Stephen Frost (sfrost@snowman.net) escribió:
Greetings,

* Hellmuth Vargas (hivs77@gmail.com) wrote:
> But could you do the following procedure?:

> pg_upgrade of the master
> rysnc with a hot standby

The above should be alright provided both the primary and the standby
are down and the instructions in the pg_upgrade docs are followed.

> arracar master
> hot standby start

So, start both the primary and the replica?  That part should be fine by
itself.

> stop hot standby and rsync the other hot standby with the migrated hot
> standby?

At some later point, shut down the replica completely, then do an rsync
from that replica to the other replica and build its hard-link tree that
way, and update anything that's changed while the 'migrated' replica was
online?  I don't see any obvious issue with that as the result should
mean that the two replicas are identical from PG's perspective from that
point moving forward.

Ultimately, it really depends on your specific environment though, of
course.  It also might not be a bad idea to do a regular backup of the
upgraded primary and then restore that to the second replica, just to
make sure you have that whole process working and to test out your
restore process.

Thanks!

Stephen


--
Cordialmente,

Ing. Hellmuth I. Vargas S.
Esp. Telemática y Negocios por Internet 
Oracle Database 10g Administrator Certified Associate
EnterpriseDB Certified PostgreSQL 9.3 Associate


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