From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Jim C. Nasby <jnasby@pervasive.com>
Cc: Tino Wildenhain <tino@wildenhain.de>
Cc: Javier Somoza <jsomoza@pandasoftware.es>
Cc: pgsql-performance@postgresql.org
Subject: Re: fsync and battery-backed caches
Date: Mon, 27 Feb 2006 20:06:13 -0500 (EST)
Message-ID: <200602280106.k1S16DK16068@candle.pha.pa.us> (raw)
In-Reply-To: <20060228002223.GW82012@pervasive.com>
Jim C. Nasby wrote:
> On Mon, Feb 27, 2006 at 11:12:57AM +0100, Tino Wildenhain wrote:
> > Javier Somoza schrieb:
> > >
> > > Hi all
> > >
> > > Is it secure to disable fsync havin battery-backed disk cache?
> > >
> > > Thx
> > >
> > No. fsync moves the data from OS memory cache to disk-adaptor
> > cache which is required to benefit from battery backup.
>
> More importantly, in guarantees that data is committed to non-volatile
> storage in such a way that PostgreSQL can recover from a crash without
> corruption.
>
> If you have a battery-backed controller and turn on write caching you
> shouldn't see much effect from fsync anyway.
We do mention battery-backed cache in our docs:
http://www.postgresql.org/docs/8.1/static/wal.html
If it is unclear, please let us know.
--
Bruce Momjian http://candle.pha.pa.us
SRA OSS, Inc. http://www.sraoss.com
+ If your life is a hard drive, Christ can be your backup. +
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To: pgsql-performance@postgresql.org
Cc: pgman@candle.pha.pa.us, jnasby@pervasive.com, tino@wildenhain.de, jsomoza@pandasoftware.es
Subject: Re: fsync and battery-backed caches
In-Reply-To: <200602280106.k1S16DK16068@candle.pha.pa.us>
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