determining the space used in / partition

[Ian Smith]

On Tue, 2 Oct 2007 08:03:00 +0200 Zbigniew Szalbot <zszalbot at gmail.com> wrote:
 > 2007/10/2, Duane Hill <d.hill at yournetplus.com>:
 > > On Tue, 2 Oct 2007 at 07:36 +0200, zszalbot at gmail.com confabulated:
 [..]
 > > > For the record. During the backup, the file system is dumped to a dir
 > > > on a USB drive called backup. Now, since the drive was unavailable,
 > > > the dump utility created /backup dir and populated it with
 > > > lists-var-l0-2007-09-30.dump.bz2 (dumping var) but of course it died
 > > > as there was not enough space on the / to do it. I mean this is what I
 > > > make of this.
 > > >
 > > > So after deleting /backup I get:
 > > > df
 > > > Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
 > > > /dev/ad0s1a    198126    74084   108192    41%    /
 > > > devfs               1        1        0   100%    /dev
 > > > /dev/ad0s1e  44511308  4217760 36732644    10%    /usr
 > > > /dev/ad0s1d  30462636  3210650 24814976    11%    /var
 > > > devfs               1        1        0   100%    /var/named/dev
 > > > /dev/da0s1c  75685352 34308200 35322324    49%    /mnt/usbck
 > >
 > > I'm still learning about all the little details about the  workings of
 > > dump myself. It would seem to me, you are dumping to /backup which is the
 > > mount point for the USB device. Would that hold true?
 > 
 > I dump to /mnt/usbck/backup. Since backup dir was not present, the
 > script created it under /

Naughty script.  It should check against doing something like that, eg
[ ! -d $backupdir ] && echo "no $backupdir - not mounted?" && exit 1

You do have a very small root filesystem for the size of your disk, so
similar disasters may need some preventing.  Something will want to use
more than 100M in /tmp sometime, so you may want to symlink /tmp to say
/usr/tmp if you haven't already.

Re hunting for 'missing' diskspace on / (or any other mounted fs), the
-x switch prevents du from crossing mountpoints, so something like .. 

# du -x -d1 / | sort -rn
146341  /
72306   /boot
49252   /root
7262    /rescue
4062    /sbin
3278    /lib
2356    /stand
2266    /etc
2114    /etc.old
2112    /etc.old.0
984     /bin
282     /libexec
8       /flash
2       /var
2       /usr
2       /usbdsk
[..]

.. takes next to no time on a small /.

Cheers, Ian