From: Evan Rempel <erempel@uvic.ca>
To: Nicholson, Brad (Toronto, ON, CA) <bnicholson@hp.com>
Cc: Chris Hoover <revoohc@gmail.com>
Cc: pgsql-admin@postgresql.org Admin <pgsql-admin@postgresql.org>
Subject: Re: Question about multiple slaves and Master loss.
Date: Wed, 07 Dec 2011 10:11:51 -0800
Message-ID: <4EDFAC67.9040809@uvic.ca> (raw)
In-Reply-To: <EC55DC235432104F8255702A8D7344D925702255@G9W0741.americas.hpqcorp.net>
References: <CAD-X90QHZpeE2_ADg1F5Gnb=QmGY4n7Yd_rhF51BM0ZNi9zriQ@mail.gmail.com>
<EC55DC235432104F8255702A8D7344D925702255@G9W0741.americas.hpqcorp.net>
Can you have a slave of a slave?
Basically set up
A --> B --> C
also
A --> D --> E
if A goes down, promote B which is protected by C
If B goes down, D is your protection for A
If C goes down, who cares.
It takes 5 machines, but would give great protection.
Evan.
Nicholson, Brad (Toronto, ON, CA) wrote:
> *From:* pgsql-admin-owner@postgresql.org
> [mailto:pgsql-admin-owner@postgresql.org] *On Behalf Of *Chris Hoover
> *Sent:* Wednesday, December 07, 2011 12:05 PM
> *To:* pgsql-admin@postgresql.org Admin
> *Subject:* [ADMIN] Question about multiple slaves and Master loss.
>
>
>
> I'm pretty sure that the answer to this question is no, but I wanted to
> verify.
>
>
>
> Given the following scenario (pg 9.0):
>
>
>
> Server A (Master), Server B (A's streaming replication Slave), Server C
> (A's streaming replication Slave)
>
>
>
> If you lose Server A, is there anyway to promote Server B to master and
> keep Server C as B's slave without having to rebuild C from a backup of B?
>
>
>
> Basically, I'd like to be able to have 2 slaves running so that when the
> master goes down, we can bring one slave online, and still have the
> ability to very quickly recover if the new master where to fail before
> server A could be recovered.
>
>
>
> Thanks,
>
>
>
> Chris
>
>
>
> Not that I am aware of. In practice though, C and B should me more or
> less equivalent so as long as you are using a differential copy like
> rsync you should be able to bring C up as a replica of B very quickly.
> There is of course a small window though where you are not protected.
>
>
>
> Brad.
>
--
Evan Rempel erempel@uvic.ca
Senior Systems Administrator 250.721.7691
Unix Services, University Systems, University of Victoria
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To: pgsql-admin@postgresql.org
Cc: erempel@uvic.ca, bnicholson@hp.com, revoohc@gmail.com
Subject: Re: Question about multiple slaves and Master loss.
In-Reply-To: <4EDFAC67.9040809@uvic.ca>
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