Quoting Richard Rauch (rauch@rice.edu):
> Re. http://mail-index.netbsd.org/netbsd-help/2002/10/28/0024.html
>
> When I asked about FFS fragmentation in the past, I was assured that FFS
> doesn't substantially suffer from fragmentation-related performance
> problems.  (Due, apparently, to the scattering of files on the disk.)
> Unless your disk is skirting the limits of its capacity, I was told, the
> disk layout strategies generally don't suffer from this.  (I'd think that
> too much scattering would result in excessive seeks, even if it helped
> enable blocks to be written in long, contiguous runs.)

And yet a client just spent a very expensive night doing overnight
emergency consulting when his 87% full disk wouldn't write any more
files due to excessive fragmentation.  It's rare and had he used
VxFS as we recommended (solaris), he wouldn't have had the problem.

Fragmentation can happen, though it's not common by any means (4 time
I've dealt with it as a problem in a decade).

dump/restore of many many gigabytes is burden some, but sometimes the
only answer to this.  I wonder what UFS2 does to address this...