Thread: Backup from a hot standby

Backup from a hot standby

From
Mikko Partio
Date:
Hi

I'm currently testing Pg 9.0.0 alpha 4 and the hot standby feature (with streaming replication) is working great. I tried to take a filesystem backup from a hot standby, but I guess that is not possible since executing "SELECT pg_start_backup('ss')" returns an error? Or can I just tar $PGDATA and copy the xlog files generated during the backup, since the server is in constant recovery mode?  In Oracle it is possible to take backups from a data guard standby, which is very useful since that way making the backups does not stress the master server.

Anyway, I must say that we are very pleased to see HS and SR features, and we hope that 9.0.0 goes to beta (and to an official release) soon!

Regards

Mikko

Re: Backup from a hot standby

From
Fujii Masao
Date:
Sorry for the delay.

On Thu, Mar 4, 2010 at 3:47 PM, Mikko Partio <mpartio@gmail.com> wrote:
> Hi
> I'm currently testing Pg 9.0.0 alpha 4 and the hot standby feature (with
> streaming replication) is working great. I tried to take a filesystem backup
> from a hot standby, but I guess that is not possible since executing "SELECT
> pg_start_backup('ss')" returns an error? Or can I just tar $PGDATA and copy
> the xlog files generated during the backup, since the server is in constant
> recovery mode?  In Oracle it is possible to take backups from a data guard
> standby, which is very useful since that way making the backups does not
> stress the master server.

You can take a base backup of the standby while it's in progress, without
calling pg_start_backup() and pg_stop_backup(). Please see the following
document.
http://developer.postgresql.org/pgdocs/postgres/backup-incremental-updated.html

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center