Subject: Re: pgbackrest periodic WAL backups?
To: pgsql-admin@postgresql.org
References: <df843a29-494a-7e72-e95a-647941979f1a@gmail.com>
 <20181209191035.GG3415@tamriel.snowman.net>
From: Ron <ronljohnsonjr@gmail.com>
Message-ID: <859f2c25-3a22-71fa-e1fa-764724183764@gmail.com>
Date: Sun, 9 Dec 2018 16:24:16 -0600
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On 12/09/2018 01:10 PM, Stephen Frost wrote:
> Greetings,
>
> * Ron (ronljohnsonjr@gmail.com) wrote:
>> I've got a full pgbackrest backup in crontab that runs weekly, and a diff
>> backup that runs nightly.  However, I can't find any way to do hourly WAL
>> backups.
>>
>> Or does "archive_command = 'pgbackrest --stanza=demo archive-push %p'" just
>> keep things automatically caught up, obviating the need for periodic WAL
>> backups (as are needed in other RDBMSs)?
> Yes and no.  With the archive command, every WAL archived will be pushed
> to the archive more-or-less immediately (or, at least, as fast as your
> system can get it there, if you enable parallel archiving in
> pgbackrest), however, WAL files have a size (by default 16MB) and if you
> have a very slowly changing system then it could possibly be hours
> between WALs being pushed to the archive by archive_command.
>
> You can address that risk by enabling archive_timeout, which will make
> PostgreSQL archive the WAL file even if it isn't full after a certain
> amount of time, reducing the potential data loss window.

I thought checkpoint_timeout forced a WAL switch.

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