Re: WAL backup

Le 28/07/2009 à 06:05:07-0600, Greg Spiegelberg a écrit
> On Tue, Jul 28, 2009 at 1:46 AM, Albert Shih <Albert(dot)Shih(at)obspm(dot)fr> wrote:
>
> Hi all
>
> I'm not sure I understand
>
>        http://www.postgresql.org/docs/8.3/interactive/
> continuous-archiving.html
>
> My problem:
>
>        I've huge database ~ 1To (soon 2 To) and I need backup.
>        I can use pgdump because it's too long to do the backup.
>        So I like to use «continous-archiving».
>
> *SNIP*
>        before this moment I use «continuous-archiving» by put in my crontab
>        something like (every hours)
>
>                rsync -av /databases/pgsql /databases/Archives
>
> is that correct ?
>
> And more important : How long I can keep this the rsync ? I mean after how
> long it's good to make a new «big backup» ?
>
>
>
> Up to the rsync in your crontab your configuration looked good.  Lose the
> cron'd rsync.
>
> The first rsync executed between pg_start_backup() and pg_stop_backup() creates
> the baseline / "full" backup of the database.  Be sure you get tablespace
> directories outside of the default PGDATA!  The archive_command adds the WAL
> logs as needed after and are the "incrementals".
>
> That's all you need for the backups.

OK. Thanks you.

At this moment I don't have tablespace ;-)

>
> How often do you need to create the baseline?  Depends how many WAL logs are
> being created and how quickly you want the recovery to be.  I have a 800 GB
> database and in one week over 4,000 WAL logs are created.  This database setup
> takes about 16-24 hours to recover.  but at least 8 hours of that is restoring
> the "full" and the remainder is applying the WAL logs.

OK. For me that should be OK because my database don't have lot of
modification in time.

>
> FWIW, I send all backup data (baseline & archived WALs) to a server which is
> responsible for backing it up to tape.  This allows the database server to be a
> database server without busying itself with actual backups.  The standby
> server, eventually, will be used as a warm standby in case the primary crashes.
>

Thanks again for your help.

Regards.
--
Albert SHIH
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Mar 28 jul 2009 15:18:25 CEST