Re: fsync and battery-backed caches

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.
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461