Hi Seth
Seth Mos [knuffie@xxxxxxxxx] wrote:
> At 23:49 5-6-2002 +0200, utz lehmann wrote:
> >Hi
> >
> >Florin Andrei [florin@xxxxxxx] wrote:
> > > On Wed, 2002-06-05 at 13:04, Thor Lancelot Simon wrote:
> > > >
> > > > More importantly, you don't *want* to use readahead because it will
> > > > waste
> > > > valuable cache space on the controller that could be used to cache small
> > > > writes.
> > >
> > > How safe is it to enable caching for writes on the controller (if you
> > > don't have a battery on it)?
> > > I mean, i configured my Mylex with "Write Through" for data-safety
> > > reasons, even though the other option ("Write Back") could offer
> > > improved performance.
> >
> >It's not (really) safe, see
> >http://oss.sgi.com/projects/xfs/mail_archive/200205/msg00510.html
>
> He is talking about a add-in card with it's own battery backup. The mail
> you referenced is about a externel raid device without a battery backup.
He sad, that the controller don't have a battery, look above. So it's the
same, a poweroutage cause lost of all unwritten data in the controller
cache.
utz
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