Re: XFS corruption during power-blackout

Dieter Nützel
2005-07-05T19:26:33Z

Am Dienstag, 5. Juli 2005 20:10 schrieb Sonny Rao:
> On Tue, Jul 05, 2005 at 08:25:11PM +0300, Al Boldi wrote:
> > Sonny Rao wrote: {
> >
> > > > >On Wed, Jun 29, 2005 at 07:53:09AM +0300, Al Boldi wrote:
> > > > >>What I found were 4 things in the dest dir:
> > > > >>1. Missing Dirs,Files. That's OK.
> > > > >>2. Files of size 0. That's acceptable.
> > > > >>3. Corrupted Files. That's unacceptable.
> > > > >>4. Corrupted Files with original fingerprint. That's ABSOLUTELY
> > > > >>unacceptable.
> > >
> > > 2. Moral of the story is: What's ext3 doing the others aren't?
> >
> > Ext3 has stronger guaranties than basic filesystem consistency.
> > I.e. in ordered mode, file data is always written before metadata, so the
> > worst that could happen is a growing file's new data is written but the
> > metadata isn't updated before a power failure... so the new writes
> > wouldn't be seen afterwards.
> >
> > }
> >
> > Sonny,
> > Thanks for you input!
> > Is there an option in XFS,ReiserFS,JFS to enable ordered mode?
>
> I beleive in newer 2.6 kernels that Reiser has ordered mode (IIRC, courtesy
> of Chris Mason),

And SuSE, ack.

ftp://ftp.suse.com/pub/people/mason/patches/data-logging

They are around some time ;-)

> but XFS and JFS do not support it. I seem to remember
> Shaggy (JFS maintainer) saying in older 2.4 kernels he tried to write
> file data before metadata but had to change that behavior in 2.6, not
> really sure why or anything beyond that.

Greetings,
Dieter

--
Dieter Nützel
@home: <Dieter () nuetzel-hh ! de>