Re: [PATCH] direct-IO API change

[Terje Eggestad <terje.eggestad@scali.com>]

On lør, 2002-10-05 at 01:23, Linus Torvalds wrote:
> On Fri, 4 Oct 2002, Andrew Morton wrote:
> > 
> > Because the file handle which we have is for /dev/raw/raw0,
> > not for /dev/hda1.
> > 
> > The raw driver binds to major/minor, not a file*.  I considered
> > changing that (change userspace to pass the open fd).  But didn't.
> 
> Ok. I'd really rather have a cleaner internal API and break the raw driver 
> for a while, than have a silly API just because the raw driver uses it.
> 
> Especially since I thought that O_DIRECT on the regular file (or block
> device) performed about as well as raw does anyway these days? Or is that
> just one of my LSD-induced flashbacks?
> 

Well, somewhat LSD induced. /dev/raw/rawN has a merit for shared disk.
Databases (Read Oracle) most notably need raw devices for parallell
databases. It would GREATLY benefit from a cluster aware fs with
O_DIRECT support, Sistina added that to their closed source GFS 5.x. 

Working with blockdevices are pure evil in my view anyway, but until a
OSS FS that is cluster aware are a part of a vanilla kernel, I'm afraid
that /dev/raw/rawN are a necessary evil 

> 		Linus
> 

TJ

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Terje Eggestad                  mailto:terje.eggestad@scali.no
Scali Scalable Linux Systems    http://www.scali.com

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