A few hours ago my root partition filled up, I moved files away from it and df reports:
# df -h Filesystem Size Used Avail Use% Mounted on /dev/hda1 183G 174G 0 100% /
So there should be 9GB free, but avail reports 0 and Use is still at 100%.
I tested as root, e.g.
# echo test >a ; cat a test
it works as expected; however as a normal user, I still get the error:
$ echo test >a ; cat a bash: echo: write error: No space left on device
The root home directory where I conducted the positive test and my home directory are on the same partition.The fstab entry is:
/dev/hda1 / ext3 noatime,defaults,errors=remount-ro 0 1