Re: Documenting pglesslog - Mailing list pgsql-hackers

Bruce Momjian wrote:
> In thinking about how to communicate to users about reducing continuous
> archiving storage requirements, I realized we don't mention pglesslog in
> our official documentation.
> 
> The attached patch documents how to use pglesslog and gzip/gunzip to
> reduce storage requirements.  Comments?
> 
> Also, I assume pg_lesslog removes the padding we use to make all WAL
> files 16MB, effectively doing the function of clearxlogtail too, right?

Applied.

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> 
> -- 
>   Bruce Momjian  <bruce@momjian.us>        http://momjian.us
>   EnterpriseDB                             http://enterprisedb.com
> 
>   + If your life is a hard drive, Christ can be your backup. +

[ text/x-diff is unsupported, treating like TEXT/PLAIN ]

> Index: doc/src/sgml/backup.sgml
> ===================================================================
> RCS file: /cvsroot/pgsql/doc/src/sgml/backup.sgml,v
> retrieving revision 2.121
> diff -c -c -r2.121 backup.sgml
> *** doc/src/sgml/backup.sgml    9 Nov 2008 17:51:15 -0000    2.121
> --- doc/src/sgml/backup.sgml    11 Jan 2009 01:41:12 -0000
> ***************
> *** 1337,1342 ****
> --- 1337,1359 ----
>         WAL files are part of the same <application>tar</> file.
>         Please remember to add error handling to your backup scripts.
>        </para>
> + 
> +      <para>
> +       If archive storage size is a concern, use <application>pg_compresslog</>,
> +       <ulink url="http://pglesslog.projects.postgresql.org"></ulink>, to
> +       remove unnecessary <xref linkend="guc-full-page-writes"> and trailing
> +       space from the WAL files.  You can then use
> +       <application>gzip</application> to further compress the output of
> +       <application>pg_compresslog</>:
> + <programlisting>
> + archive_command = 'pg_compresslog %p - | gzip > /var/lib/pgsql/archive/%f'
> + </programlisting>
> +       You will then need to use <application>gunzip</> and
> +       <application>pg_decompresslog</> during recovery:
> + <programlisting>
> + restore_command = 'gunzip < /mnt/server/archivedir/%f | pg_decompresslog - %p'
> + </programlisting>
> +      </para>
>       </sect3>
>   
>       <sect3 id="backup-scripts">

> 
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--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +