Re: no universally correct setting for fsync

On Fri, May 7, 2010 at 9:47 AM, Kevin Grittner
<Kevin.Grittner@wicourts.gov> 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