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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Graeme B. Bell <graeme.bell@nibio.no>
Cc: Wes Vaske (wvaske) <wvaske@micron.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: New server: SSD/RAID recommendations?
Date: Tue, 07 Jul 2015 23:05:06 +0300
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On 07/07/2015 10:59 PM, Graeme B. Bell wrote:
> Cache flushing isn't an atomic operation though. Even if the ordering
> is right, you are likely to have a partial fsync on the disk when the
> lights go out - isn't your FS still corrupt?

If the filesystem is worth its salt, no. Journaling filesystems for 
example rely on the journal to work around that problem, and there are 
other mechanisms.

PostgreSQL has exactly the same problem and uses the WAL to solve it.

- Heikki



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