Incremenats as big as full

Hi

This is not realy an amanda problem but I thought one of you may have seen this 
problems before.

We have a filesytem which contians files that are basically static. However
when they are backed up the incrementals are almost as big as the full backups.

server> amadmin sir-1 info advisor1 /advisor/video

Current info for advisor1 /advisor/video:
  Stats: dump rates (kps), Full:  2270.0, 2231.0, 2274.0
                    Incremental:  2119.0, 2250.0, 2275.0
          compressed size, Full:  62.1%, 62.1%, 62.1%
                    Incremental:  66.6%, 66.6%, 66.6%
  Dumps: lev datestmp  tape             file   origK   compK secs
          0  20030618  sir-1-20           54 10650330 6617775 2915
          1  20030703  sir-1-10            7  9873700 6578667 3104

This happens with dump and gntar backups. If I do a find on the filesystem it 
claims that no files have been modified in the last 90 days.

advisor1:/tmp/amanda # find /advisor/video/* -type f -mtime -90 -ls

advisor1:/tmp/amanda # dump --version
dump: invalid option -- -
dump 0.4b26 (using libext2fs 1.26 of 3-Feb-2002)
usage:  dump [-0123456789acMnqSu] [-B records] [-b blocksize] [-d density]
             [-e inode#,inode#,...] [-E file] [-f file] [-h level]
             [-I nr errors] [-j zlevel] [-s feet] [-T date] [-z zlevel] 
filesystem
        dump [-W | -w]

advisor1:/tmp/amanda # tar --version
tar (GNU tar) 1.13.18
Copyright 2000 Free Software Foundation, Inc.
This program comes with NO WARRANTY, to the extent permitted by law.
You may redistribute it under the terms of the GNU General Public License;
see the file named COPYING for details.
Written by John Gilmore and Jay Fenlason.

advisor1:/tmp/amanda # cat /etc/SuSE-release
SuSE Linux 8.0 (i386)
VERSION = 8.0

advisor1:/tmp/amanda # uname -a
Linux advisor1 2.4.20 #1 SMP Fri Jan 10 15:32:51 GMT 2003 i686 unknown

advisor1:/tmp/amanda # df -h /advisor/video/
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2              17G   11G  6.0G  63% /advisor/video

advisor1:/tmp/amanda # mount -v | grep /advisor/video
/dev/sda2 on /advisor/video type ext3 (rw)


Anthony Worrall
School IT Networking Coordinator
School of Systems Engineering
The University of Reading,
Whiteknights, PO Box 225
Reading,
Berkshire, UK
RG6 6AY
Tel:   +44 (0)118 931 8610
Fax:   +44 (0)118 975 1822
Email: Anthony.Worrall AT Reading.ac DOT uk