Re: Poor performance of btrfs with Postgresql

On 04/21/2011 06:16 AM, Henry C. wrote:
> Since Pg is already "journalling", why bother duplicating (and pay the
> performance penalty, whatever that penalty may be) the effort for no real
> gain (except maybe a redundant sense of safety)?  ie, use a
> non-journalling battle-tested fs like ext2.
>

The first time your server is down and unreachable over the network
after a crash, because it's run fsck to recover, failed to execute
automatically, and now requires manual intervention before the system
will finish booting, you'll never make that mistake again.  On real
database workloads, there's really minimal improvement to gain for that
risk--and sometimes actually a drop in performance--using ext2 over a
properly configured ext3.  If you want to loosen the filesystem journal
requirements on a PostgreSQL-only volume, use "data=writeback" on ext3.
And I'd still expect ext4/XFS to beat any ext2/ext3 combination you can
come up with, performance-wise.

--
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us
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