Re: O_DIRECT please; Sybase 12.5

Daryll Strauss
2001-07-03T15:10:41Z

On Tue, Jul 03, 2001 at 10:42:53AM +0100, Stephen C. Tweedie wrote:
> On Fri, Jun 29, 2001 at 02:39:00AM -0700, Dan Kegel wrote:
>
> > It supports raw partitions, which is good; that might satisfy my
> > boss (although the administration will be a pain, and I'm not
> > sure whether it's really supported by Dell RAID devices).
>
> All block devices support raw IO --- the raw IO mechanism talks to the
> device driver through the normal kernel-internal block IO entry
> points.
>
> > I'd prefer O_DIRECT :-(
>
> Andrea Arcangeli has already posted patches you can try for ext2. The
> functionality isn't in the mainline kernel yet, though.

I recall hearing about a problem with the md device and raw IO. It was
something about the block sizes not matching causing performance
problems. Has anything been done to improve those issues?

- |Daryll