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DragonFly bugs List (threaded) for 2005-02
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Re: Off-Topic Question


From: David Rhodus <sdrhodus@xxxxxxxxx>
Date: Wed, 16 Feb 2005 13:12:51 -0500

On Wed, 16 Feb 2005 18:57:43 +0100, Joerg Sonnenberger
<joerg@xxxxxxxxxxxxxxxxx> wrote:
> On Wed, Feb 16, 2005 at 05:49:59PM +0000, Eduardo Tongson wrote:
> > > (a) softdep is complex. *very* complex.
> > > (b) softdep doesn't solve the problems of fast reboots after crash
> > > (c) softdep doesn't allow replaying changes for off-site synchronisation
> > >
> > > I consider softdep a useful concept for a filesystem, it can really
> > > help for those filesystems we can't add a journaling later on top.
> > > But having native journaling support can be much better.
> > >
> > > Joerg
> > >
> >
> > So that's the problem with softdep.
> > Can you pls similarly point out the flaws of background fsck
> 
> Background fsck depends on the snapshot mechanism which is a very crude
> hack for itself. It doesn't solve the essential problem of having to do
> a fsck, it just puts it into the background. You still have massive
> IO going on.
> 
> Basically, if you believe that the softdep code is correct and don't care
> about some missing free space, you can hack out the "mount dirty fs rw"
> check.
> 
> Joerg
> 

I have done this testing before on machines, and the end result is
always total filesystem corruption.

-- 
                                            -David
                                            Steven David Rhodus
                                            <drhodus@xxxxxxxxxxx>



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