Filesystem Size Used Avail Capacity Mounted on /dev/ada0p2 1G 624M 302M 67% / devfs 1.0k 1.0k 0B 100% /dev /dev/ada0p4 503M 20k 463M 0% /tmp /dev/ada0p5 9.9G 1.7G 7.3G 19% /var /dev/ada0p6 903G 903G -71G 109% /usr devfs 1.0k 1.0k 0B 100% /var/named/dev
From your output, the disk
/var/dev/ada0p6 seems to be so full that you are now using "reserved space". Usually, 8-10% of disk space are "reserved" (i.e. only
root processes can allocate space once disk usage exceeds 90%). Once this happens, free space is reported as a negative number.
The answer above is correct in that the reserved space is being subtracted from that available, leaving you with a negative amount of space usable by non-root users.
You ask how to remove the error. You can either—
- free disk space;
- expand the filesystem; or
- reduce the size of the reserved area.
On an ext3/4 filesystem you use
tune2fs to set this percentage like this:
# sudo tune2fs -m 2 /dev/ada0p6
This will set the reserved space to 2% of total disk space. Beware when doing this, as reducing it too far may allow ordinary users to fill the filesystem and cause system-wide problems.