Re: Backup strategy using 'wal_keep_segments'

Hi Stephen,

Thanks for replying.

I would actually be an advocate for using a proper archive_command in order to facilitate a proper (Per the documentation) PITR and backup strategy.

However, a colleague had suggested such a creative approach (Possibly, less administrative overhead, ease of maintenance? I'm not sure) and I struggled to find any evidence online in blogs/white-papers/documentation that this was a feasible approach. That said, I couldn't find any info rejecting it as a method either, which led me to post here. Essentially, this was a difference of opinion on approach, and I was looking to gather information in order to make an informed opposing argument.

My only thought now would be how could I decipher, within the sequence chain of WAL files, up to which file has the "archival" progressed to. i.e. which files are not susceptible to being called upon again for restartpoints/checkpoints. That is, where is my absolute point (or file) of archival using something along the lines of 'pg_current_xlog_location'.

Regards,

Ruan

________________________________
From: Stephen Frost <sfrost(at)snowman(dot)net>
Sent: 30 October 2017 16:41:11
To: Rhhh Lin
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] Backup strategy using 'wal_keep_segments'

Greetings,

* Rhhh Lin (ruanlinehan(at)hotmail(dot)com) wrote:
> A colleague recently suggested that instead of implementing an 'archive_command' to push archivable WALs to a secondary location (for further backup to tape for example), we could instead persist the WAL files in their current location by setting the "wal_keep_segments" parameter to an extreme value e.g. 1000 and have the 'archive_command' do nothing.

Michael's points are good and I wouldn't recommend using this archive
command either, but what isn't clear to me is what you're actaully
trying to solve by using such a method..? You haven't said anywhere
what's wrong with archive_command (I know that there certainly are some
things wrong with it, of course, but there are solutions to a number of
those issues that isn't a hack like this ...).

Thanks!

Stephen