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.)

I would also think that as files get (re)written over time, disk blocs
would necessarily become less cohesive.  But, what do I know?  (^&


It may be worth noting, however, that I had a 20GB Maxtor drive give me
some serious problems w.r.t. performance.  As near as I could tell
(according to my memory), seek times were dropping off horribly, which had
terrible impact on most real-life file operations.

E.g., during NetBSD boot, the spinnig marker indicating kernel load
progress would start and stop.  I even went so far as to wipe the disk and
do a fresh NetBSD install.  The problems persisted.

In the end, I managed to get Maxtor to honor their warranty (even though I
was not able to run their BillOS-only diagnostic software), and my new
drive performed vastly better.  (Though I've noticed some hints of return
to old problems recently...  However, these problems returned right after
the upgrade to NetBSD 1.6, so it may just be block-scattering---despite
assurances I've been given that NetBSD's FFS doesn't really suffer from
fragmentation.)


The short of it: You can always "defragment" by backup/wipe/restore.  (^&
(This isn't such a bad option as disk drives become so cheap; especially
if you decide to invest in a second drive as a backup medium anyway...)
You might also consider the possibility of a disk drive problem.


  ``I probably don't know what I'm talking about.'' --rauch@math.rice.edu