Re: Taking hot backup of slave node in postgres (master-slave config with repmgr)

Hi,

I don't see any differences if you take backup from master or cold from slave, differences are only in conf files.
In my environment I'm only doing full backup using pg_backup of master server (it will skip configuration files), create copy of conf. Files and that is.

Of cource do recovery test.

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Dubravko Sever
Sektor za računalne sustave
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From: pgsql-admin-owner(at)postgresql(dot)org [mailto:pgsql-admin-owner(at)postgresql(dot)org] On Behalf Of Andrey Nikitin
Sent: Tuesday, January 14, 2014 1:37 PM
To: pgsql-admin(at)postgresql(dot)org
Subject: [ADMIN] Taking hot backup of slave node in postgres (master-slave config with repmgr)

I have a #postgresql setup with master-slave configuration using repmgr. im struggling with taking a consistent snapshot backup (pg_start_backup) of the slave node, this is due the fact that the slave is in recovery, hence read-only mode.

i need both the master and the slave snapshots to speedup the recovery process (if taken only on 1 node, in case of recovery the slave needs to be rebuild from scratch). any advice of how to take a consistent snapshot of slave node? (master is no problem).

currently these are the approaches im checking:

1.shutting down slave node and take a cold snapshot backup.

1. pg_start_backup on master and hopefully it will reflect consistent state on slave (with the WAL shipping) - any confirmation on this one?

2. stop replication, take hot backup of slave using regular methods and then starting replication again - as far as i tested, not possible because as the replication is stopped, each node becomes independent and has its own timeline, thus require the nodes to resync in order to function again in master-slave config.

3. make a switch over before taking the backup - dont like this option, dont think is a correct approach to make a switch-over each time i want to take a backup.

anything i missed? have you implemented it using different methods?

thanks.