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From: Robert Haas <[email protected]>
To: Kevin Grittner <[email protected]>
Cc: [email protected]
Subject: Re: no universally correct setting for fsync
Date: Fri, 7 May 2010 10:00:50 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

On Fri, May 7, 2010 at 9:47 AM, Kevin Grittner
<[email protected]> wrote:
> Someone just posted to the -admin list with a database corrupted
> while running with fsync=off.  I was all set to refer him to the
> documentation explaining why he should stop doing this, but to my
> surprise the documentation waffles on the issue way past what I
> think is reasonable.
>
> http://www.postgresql.org/docs/8.4/interactive/runtime-config-wal.html#GUC-FSYNC
>
> There are dire-sounding statements interspersed with:
>
> | using fsync results in a performance penalty
>
> | Due to the risks involved, there is no universally correct setting
> | for fsync.
>
> | If you trust your operating system, your hardware, and your
> | utility company (or your battery backup), you can consider
> | disabling fsync.
>
> Isn't this a little too rosy a picture to paint?

I agree.  I've always thought this part of the documentation made
setting fsync=off much more reasonable than I feel it to be.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company

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