File system at more than 100%

[michaelrmgreen]

df -h gives this:

Filesystem Size Used Avail Capacity Mounted on
/dev/ad0s2a 496M 481M -25M 105% /
devfs 1.0K 1.0K 0B 100% /dev
/dev/ad0s2e 496M 120M 336M 26% /tmp
/dev/ad0s2f 60G 2.6G 53G 5% /usr
/dev/ad0s2d 1.2G 36M 1.1G 3% /var


I remember reading somwhere about the explanation for the ability to go beyond 100%, but can't now find it. Can someone refresh my failing memory and more importantly advise how I got in this mess and what to do about it? TIA

[michaelrmgreen]

Oops, the tabs/spaces for the table seem to have gone awol. Sorry.

[Carpetsmoker]

If you want tabs/spaces to be preserved, you need to use:

[code]
... stuff ...
[/code]


Anyway,

From the FreeBSD FAQ

9.27. How is it possible for a partition to be more than 100% full?

A portion of each UFS partition (8%, by default) is reserved for use by the operating system and the root user. df(1) does not count that space when calculating the Capacity column, so it can exceed 100%. Also, you will notice that the Blocks column is always greater than the sum of the Used and Avail columns, usually by a factor of 8%.

For more details, look up the -m option in tunefs(8).

You may want to remove some stuff on your / partition, to see where all teh space is going you can use something like:
# du -hxd1 /

[michaelrmgreen]

On the cycle ride between one of my places of work and another I have had the time and freedom from interruptions to think about this problem.

The origins of the problem go back to a time when I used a separate partition (data) for the system data. This setup proved impossible to recreate using sysinstall after 4.x (something to do with GEOM as I recall) so I created a directory called 'data' in root. Clearly the default size for root is 500Mb or thereabouts and it just filled up.

The simplest solution seems to be to move the data files from /data to /usr/data and adjust the paths in the applications to suit.

I've been calling myself some very rude names since I realised what I did. Anyway thanks to all, and let that be a lesson in the need for considering the implications of what seems like a minor system change!

[Carpetsmoker]

You can also just symlink /data to /usr/data.