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Message-ID: <4DADAA5C.6040107@gmail.com>
Date: Tue, 19 Apr 2011 17:29:32 +0200
From: rudi <rudolone@gmail.com>
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To: pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: Streaming replication: rsync to switchover
References: <4DAC7205.8080203@kemen.it>
	<BANLkTikrqROJjNiVpmkZorkPM7nUYHZUAw@mail.gmail.com>
	<4DAD52D8.1090006@gmail.com> <20110419121105.GA17761@cns.vt.edu>
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On 04/19/2011 02:11 PM, Ray Stell wrote:
> On Tue, Apr 19, 2011 at 11:16:08AM +0200, rudi wrote:
>> On 04/19/2011 10:09 AM, Gerhard Hintermayer wrote:
>> So you keep the old pg_xlog
>
> the admin book says to exclude old pg_xlog
>

Which book is this?

So I guess something like this (from new master to former master) should 
be safe:

$ psql -c "SELECT pg_start_backup('switchover base backup')"
$ rsync -av /var/lib/postgresql/9.0/main/ --delete --exclude server.crt 
--exclude server.key --exclude recovery.* --exclude postmaster.pid 
--exclude archive $FORMER_MASTER_ADDRESS:/var/lib/postgresql/9.0/main/
$ psql -c "SELECT pg_stop_backup()"

What about the archiving directory of the former slave (now master)?
It should be cleaned guess, in case it will be slave again. If I look at 
that directory, after a failover it is not empty.
This looks strange to me because pg_cleanup_archive should have already 
cleaned it.

BTW, is there any documentation about the logic behind pg_xlog 
filenames? It is really obscure and this makes really hard understanding 
what's going on. I'm sure that most recent mtime gives me the active 
WAL, and I can match somehow this:

Latest checkpoint location:           7/F70021A0
Prior checkpoint location:            7/F7002110
Latest checkpoint's REDO location:    7/F7002168
Latest checkpoint's TimeLineID:       2

with this filename: 0000000200000007000000F7

and that's all.

thanks,

-- 
rd

Peel your own image from the mirror.
Sit. Feast on your life.