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wal shipping/pg_standby docs patch 3+ messages / 2 participants [nested] [flat]
* wal shipping/pg_standby docs patch @ 2009-03-25 19:20 Frank Wiles <[email protected]> 2009-03-26 02:04 ` Re: wal shipping/pg_standby docs patch Tom Lane <[email protected]> 0 siblings, 1 reply; 3+ messages in thread From: Frank Wiles @ 2009-03-25 19:20 UTC (permalink / raw) To: pgsql-docs Hello, It has been awhile since I setup a warm standby server, so I dutifully followed the documentation. However, the documentation specifically suggests using 'cp -i' as the archive command. Granted, it does say that it is only a suggestion and not a recommendation, but does specifically mention it for Linux. Wasn't three days before I was bitten by transferring a WAL file before it was fully copied into the archive location. Attached is a patch that makes the suggestion be 'rsync -avr' in both backup.sgml and pg_standby.sgml. Thanks! -- Frank Wiles Revolution Systems | http://www.revsys.com/ [email protected] | (800) 647-6298 Attachments: [text/x-diff] rsync-doc.patch (1.4K, 2-rsync-doc.patch) download | inline diff: diff -ur postgresql-snapshot/doc/src/sgml/backup.sgml my-postgresql/doc/src/sgml/backup.sgml --- postgresql-snapshot/doc/src/sgml/backup.sgml 2009-03-05 13:50:03.000000000 -0600 +++ my-postgresql/doc/src/sgml/backup.sgml 2009-03-25 13:35:24.000000000 -0500 @@ -564,7 +564,7 @@ </programlisting> which will copy archivable WAL segments to the directory <filename>/mnt/server/archivedir</>. (This is an example, not a - recommendation, and might not work on all platforms.) After the + recommendation, and might not work on all platforms. It is highly recommend you use a tool that does atomic copies such as <programlisting>rsync -arv %p...</programlisting>) After the <literal>%p</> and <literal>%f</> parameters have been replaced, the actual command executed might look like this: <programlisting> diff -ur postgresql-snapshot/doc/src/sgml/pgstandby.sgml my-postgresql/doc/src/sgml/pgstandby.sgml --- postgresql-snapshot/doc/src/sgml/pgstandby.sgml 2009-02-27 03:30:21.000000000 -0600 +++ my-postgresql/doc/src/sgml/pgstandby.sgml 2009-03-25 13:27:42.000000000 -0500 @@ -207,7 +207,7 @@ <para>On Linux or Unix systems, you might use:</para> <programlisting> -archive_command = 'cp %p .../archive/%f' +archive_command = 'rsync -arz %p .../archive/%f' restore_command = 'pg_standby -l -d -s 2 -t /tmp/pgsql.trigger.5442 .../archive %f %p %r 2>>standby.log' </programlisting> ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: wal shipping/pg_standby docs patch 2009-03-25 19:20 wal shipping/pg_standby docs patch Frank Wiles <[email protected]> @ 2009-03-26 02:04 ` Tom Lane <[email protected]> 2009-03-26 16:08 ` Re: wal shipping/pg_standby docs patch Frank Wiles <[email protected]> 0 siblings, 1 reply; 3+ messages in thread From: Tom Lane @ 2009-03-26 02:04 UTC (permalink / raw) To: Frank Wiles <[email protected]>; +Cc: pgsql-docs Frank Wiles <[email protected]> writes: > Attached is a patch that makes the suggestion be 'rsync -avr' in both > backup.sgml and pg_standby.sgml. Seems to me the first question to ask is exactly why you got "bit" by cp. I doubt that rsync will provide a magic answer. regards, tom lane ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: wal shipping/pg_standby docs patch 2009-03-25 19:20 wal shipping/pg_standby docs patch Frank Wiles <[email protected]> 2009-03-26 02:04 ` Re: wal shipping/pg_standby docs patch Tom Lane <[email protected]> @ 2009-03-26 16:08 ` Frank Wiles <[email protected]> 0 siblings, 0 replies; 3+ messages in thread From: Frank Wiles @ 2009-03-26 16:08 UTC (permalink / raw) To: Tom Lane <[email protected]>; +Cc: pgsql-docs On Wed, Mar 25, 2009 at 9:04 PM, Tom Lane <[email protected]> wrote: > Frank Wiles <[email protected]> writes: >> Attached is a patch that makes the suggestion be 'rsync -avr' in both >> backup.sgml and pg_standby.sgml. > > Seems to me the first question to ask is exactly why you got "bit" by > cp. I doubt that rsync will provide a magic answer. > > regards, tom lane Hi Tom, Using the example in the docs in both places suggests using cp to copy to your archive location, which isn't atomic. This leaves open the possibility of transferring to your warm standby server part of a WAL file. In my case I was using rsync in cron to pull from the "master" onto the warm standby server. Ran fine for 3 days, then I transferred a 14MB and a 8.2MB WAL file. Basically being unlucky and transferring it at just the wrong time. This obviously hosed the warm standby and I had to go through the whole backup procedure again. Using rsync, as it is atomic, prevents this. -- Frank Wiles Revolution Systems | http://www.revsys.com/ [email protected] | (800) 647-6298 ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2009-03-26 16:08 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2009-03-25 19:20 wal shipping/pg_standby docs patch Frank Wiles <[email protected]> 2009-03-26 02:04 ` Tom Lane <[email protected]> 2009-03-26 16:08 ` Frank Wiles <[email protected]>
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