defrag

[Jerry McAllister]

On Thu, Mar 01, 2007 at 05:17:38PM -0500, Jerry McAllister wrote:

> On Fri, Mar 02, 2007 at 08:51:00AM +1100, Norberto Meijome wrote:
> 
> > On Thu, 1 Mar 2007 19:22:32 +0100 (CET)
> > Wojciech Puchar <wojtek at tensor.3miasto.net> wrote:
> > 
> > > backup+restore will be defrag
> > 
> > you mean : backup, format, (reinstall if needed, depending on method of backup)
> > and restore - or simply restore on top (if you backed up everything and can
> > access your drive offline).
> > 
> > simply overwriting the existing files won't change anything, would it? You'd
> > need a clean slate to do a defrag this way...
> 
> Well, it would do some, but for the greatest effect, you would need:
>   dump + rm -rf * + restore
> That would get it all.
> 
> You could be really extreme and do:
>   dump + newfs + restore 
> if you wanted to, to be sure of a clean file system
> 
> You would not need a reformat (though some people really mean newfs
> when they say reformat) and you would not need any reinstall.  But,
> if you did this on the root partition, you would have to to the
> restore from some other boot such as on a different disk or from
> the fixit utility on the installation CD.   That shouldn't be
> necessary for any other file system unless you foolishly put /sbin
> in a partition other than /  (root).

Of course, I should have re-emphasized that this is not needed.
You will not improve performance.   Its only value might be to exercise
every used file block on the filesystem to make sure it is still
readable.    And for that you don't need to nuke and rewrite things.
Just doing the backup (which you should do anyway) will read up all
used file space (except what you might have marked as nodump).
 -- or the other possible value - to placate mal-informed management.

////jerry

> 
> ////jerry
> 
> > _________________________
> > {Beto|Norberto|Numard} Meijome
> > 
> > Software isn't released.... it escapes.
> > 
> > I speak for myself, not my employer. Contents may be hot. Slippery when wet.
> > Reading disclaimers makes you go blind. Writing them is worse. You have been
> > Warned.
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