Re: bio too big device

Jens Axboe (axboe@suse.de)
Wed, 12 Mar 2003 16:11:17 +0100


On Wed, Mar 12 2003, Alan Cox wrote:
> On Wed, 2003-03-12 at 09:09, Jens Axboe wrote:
> > On Wed, Mar 12 2003, Andre Hedrick wrote:
> > >
> > > So lets dirty list the one drive by Paul G. and be done.
> > > Can we do that?
> >
> > Who cares, really? There's not much point in doing it, we're talking 248
> > vs 256 sectors in reality. I think it's a _bad_ idea, lets just keep it
> > at 255 and avoid silly drive bugs there.
>
> 255 trashes your performance, 128 will perform far better with most
> setups. This is especially true with raid setups. I'd much rather we

Then go with 128. I'd like to stress again that _if_ you get worse
performance it's not due to the request being a bit smaller, but indeed
because 248 can cause badly aligned requests.

> got the IDE layer using 256 block writes even if we have to limit it
> to more modern drives by some handwaving (8Gb+ say)

Does Windows use 256 sector requests or not? If not, then I'd sure don't
want to do it in Linux, the handwaving doesn't mean anything then.

-- 
Jens Axboe

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