Re: PG Upgrade with hardlinks, when to start/stop master and replicas

Greetings,

* Martín Fernández (fmartin91(at)gmail(dot)com) wrote:
> Thanks for information! I've refactor our migration scripts to follow the suggestions. 

Please don't top-post on these mailing lists.

> 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.

Not sure which standby we're talking about here, but in general, yes, as
long as you haven't actually started the system after the
pg_upgrade/rsync, you should be able to blow away the new cluster that
pg_upgrade/rsync created and start the old cluster back up and promote
it (if necessary) and use it.

Note that you should *not* need to do anything with pg_control, I have
no idea what you're referring to there, but the old cluster should have
the pg_control file and all the catalog tables in place from before the
pg_upgrade/rsync (those aren't touched during the pg_upgrade/rsync
process) and you would just need to start up the old binaries pointing
at the old PG data directory and everything should just work.

Thanks!

Stephen