Re: XFS and write barriers.

[David Chinner <dgc@sgi.com>]

On Thu, Mar 29, 2007 at 04:56:21PM +0200, Martin Steigerwald wrote:
> Am Montag 26 März 2007 schrieb David Chinner:
> 
> > > Is there some mount flag to say "cope without barriers" or "require
> > > barriers" ??
> >
> > XFs has "-o nobarrier" to say don't use barriers, and this is
> > *not* the default. If barriers don't work, we drop back to "-o
> > nobarrier" after leaving a loud warning inthe log....
> 
> Hello David!
> 
> Just a thought, maybe it shouldn't do that automatically, but require the 
> sysadmin to explicitely state "-o nobarrier" in that case. 

And prevent most existing XFS filesystems from mounting after
a kernel upgrade? Think about the problems that might cause
with XFs root filesystems on hardware/software that doesn't
support barriers....

Default behaviour is tolerant - it tries the safest method
known and if it can't use that it tells you and then continues
onwards. That's a good default to have.

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group