Date: Fri, 5 Feb 2016 16:09:28 -0500
From: Stephen Frost <sfrost@snowman.net>
To: Dave Johansen <davejohansen@gmail.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: Setting up streaming replication with new server as
 master?
Message-ID: <20160205210928.GB3331@tamriel.snowman.net>
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* Dave Johansen (davejohansen@gmail.com) wrote:
> On Fri, Feb 5, 2016 at 1:54 PM, Stephen Frost <sfrost@snowman.net> wrote:
> > * Dave Johansen (davejohansen@gmail.com) wrote:
> > > So will pg_basebackup keep copying the new data that is added over the
> > > weekend until I tell it to stop? If so, then on Monday, can I close
> > things
> > > down, wait for the WAL to finish, swap the roles of the 2 server and =
then
> > > restart?
> >
> > No, pg_basebackup will take a snapshot of the current system,
> > essentially.  You can set up the new system to connect to the current
> > system, using recovery.conf, to pull the WAL records and apply them to
> > the new server.
> >
>=20
> So do I set that up before running pg_basebackup?
>=20
> Or in other words, pg_basebackup will get all of the existing data and th=
en
> the setup using recovery.conf will get the new data?

Right.  Note that to use pg_basebackup or to have a replica connect to
the existing system, you need to have archive_mode set to archive or
higher (and you should at least do hot_standby, really), and have
max_wal_senders set higher than 0 (I tend to set it to about 3, just
because it uses little in the way of resources, etc).  If you have a
high transaction rate, you might also want to set wal_keep_segments up a
bit.

Thanks!

Stephen

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