Re: PostgreSQL replication failover

You can use different tools which detects if primary fails and
automatically promotes standby.

To assure all data on standby you should use synchronous replication.

On Wed, 13 Jan 2021, 6:54 pm Pepe TD Vo, <pepevo(at)yahoo(dot)com> wrote:

> >>If you shut down the primary server cleanly, all changes will be
> replicated,so you should be good.
>
> >>During a failover, that is, if the primary suddenly fails, there is
> always
> the possibility that you lose some transactions, unless you use synchronous
>
> you said above which I don't need to run promote to make it failover as
> long as I set synchronous on? The last couple of weeks I have a failure
> on the primary server and can't run on a slave. It picks up as reading mode
> only.
>
>
>
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>
> On Wednesday, January 13, 2021, 06:25:53 AM EST, Laurenz Albe <
> laurenz(dot)albe(at)cybertec(dot)at> wrote:
>
>
> On Wed, 2021-01-13 at 09:27 +0100, Jan Peters wrote:
> > we are running postgresqlserver on s390 zLinux machines. The distribution
> > is RedHat 7 and RedHat 8, so we do not have the many x86 tools
> available.
> >
> > We always run 2 instances with a replication (streaming) async mode, the
> replica
> > is in hot_standby and we use it for read-only accesses. About the setup
> we have the following question:
> >
> > How is an orderly failover accomplished? Our current procedure is.
> >
> > 1. primary stop
> > 2. promote replica to primary
> > 3. create standby.signal on old primary
> > 4. change primary_conninfo on old primary
> > 5. start old primary as new replica
> >
> > Is this processing correct? Are there any other steps that simplify a
> failover?
> > How can we be sure that all changes have been transferred from the old
> master to the replica?
>
> What you describe is not a failover, but a switchover.
>
> If you shut down the primary server cleanly, all changes will be
> replicated,
> so you should be good.
>
> During a failover, that is, if the primary suddenly fails, there is always
> the possibility that you lose some transactions, unless you use synchronous
>
> replication.
>
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>
>
>
>
>