Re: Off-Topic Question

[David Rhodus <sdrhodus@xxxxxxxxx>]

On Wed, 16 Feb 2005 18:21:21 +0100, Joerg Sonnenberger
<joerg@xxxxxxxxxxxxxxxxx> wrote:
> On Wed, Feb 16, 2005 at 06:09:48PM +0100, Tom Hummel wrote:
> > Can you point me to the necessity of adding journaling to UFS? I thought
> > Softdeps haven been a comparable solution to the same problem journaling
> > addresses. Both's performance penaltys over async metadata writes seem
> > to happen in the same universe.
> 
> (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
> 

Soft updates and journaling are not the same thing.  I haven't done
any testing yet but I don't think FFS would perform as a very good
modern filesystem if we remove soft updates without changing the
behaviour of the filesystem.

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