determining the space used in / partition

[Zbigniew Szalbot]

hello,

Through df I realized my / partiotion is out of space:
Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
/dev/ad0s1a    198126   196070   -13794   108%    /
devfs               1        1        0   100%    /dev
/dev/ad0s1e  44511308  4217762 36732642    10%    /usr
/dev/ad0s1d  30462636  3210580 24815046    11%    /var
devfs               1        1        0   100%    /var/named/dev
/dev/da0s1c  75685352 34308200 35322324    49%    /mnt/usbck

How can I determine what occupies the space in it? That is, it is not
big as you can see. So I issued:
du -hs /
but it was taking ages (I am not sure but maybe du -hs counts all
directories on the HD?

Anyway, I do not really know where to look what has eaten the / space.
Were it for /usr or /var,  it would be obvious to me where to look for
information.

Many thanks!

zbigniew szalbot