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


From: Joerg Sonnenberger <joerg@xxxxxxxxxxxxxxxxx>
Date: Wed, 16 Feb 2005 18:57:43 +0100
Mail-followup-to: bugs@crater.dragonflybsd.org

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



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