Re: hdd defrag

[idalton@ferret.phonewave.net]

On Fri, Apr 20, 2001 at 04:54:57PM -0300, Peter Cordes wrote:
> On Fri, Apr 20, 2001 at 11:14:35AM -0700, Jeff Coppock wrote:
> > I was wondering if it's necessary to defragment ext2fs or reiserfs?  I do this on a regular basis with my Windoze machines.
> > 
> > What utilities could be used for this, if it's recommended?
> 
>  ext2 is smart, and does a good job of not fragmenting files.  search the
> web, lots of good info is out there.  Reiserfs is also smart like that.
> (BTW, it's the allocation algorithms in particular that are smart.  They put
> new files where they will have room to grow without fragmenting.)
> 
>  If you have an almost-full filesystem, there won't be room to avoid
> fragmentation, so you should avoid that.  ext2 is most efficient when less
> than 90% full, or so.  (I don't know what a good cutoff value should be, but
> 90% is probably reasonable.)
> 
>  There is an ext2defrag or something around, so you can use that if you want
> to.  Most people never defrag their FSes, and have no problems with them.

My own experiences with defragging ext2 have generally been: Don't. On
the other hand, if you happen to shrink an ext2 partition with some
utility like Partition Magic (and I haven't tried ext2 resize yet) it'll
actually help to run a defrag on it afterward. On the other hand, you
can't quit in the middle of defragging, and you can't defrag the current
root partition.

-- Ferret
who learned the hard way, when the power failed during a defrag once.