Extremely large level 1 backups with dump

[Peter Tenenbaum <peter.g.tenenbaum@gmail.com>]

I've been using dump to perform backups of my home Debian workstation (I run squeeze, btw).  I do a weekly level 0 dump and daily level 1 dumps.

For some reason the level 1 backups are almost as large as the level 0 (the level 0 is 57.9 GB and the level 1 is 51.6 GB), even though we clearly don't modify anything like that many files in the interval from one day to the next.  The commands that I am using for these backups are of the form:

dump -0u -f "/media/FreeAgent Drive/filename0" -A "media/FreeAgent Drive/archive0" /dev/md3
dump -1u -f "/media/FreeAgent Drive/filename1" -A "media/FreeAgent Drive/archive1" /dev/md3

where /dev/md3 is my RAID1 array root partition.

Any idea why the level-1 backups are almost as large as the level-0?

Thanks in advance,
-PT