bash: echo: write error: No space left on device

I am using Ubuntu Linux and using this as PHP server hosting the scripts and sites in /var/www/. I am getting bash: echo: write error: No space left on device but there is huge space left on the device. I have found on google about this issue but no one suits my problem as people were getting this error after running some commands but I am getting it just after running gksudo nautilus yesterday,

I am unable to umount any drive please suggest me what to do

I have run $ sudo apt-get clean

I have run $ sudo apt-get autoremove

I am getting this message after running `$ df -k

Filesystem     1K-blocks      Used Available Use% Mounted on
/dev/sda7       93956704  89329640         0 100% /
udev             1989324         4   1989320   1% /dev
tmpfs             799256      1076    798180   1% /run
none                5120         0      5120   0% /run/lock
none             1998132      3324   1994808   1% /run/shm
overflow            1024        16      1008   2% /tmp
/dev/sda2      240367612 192464952  47902660  81% /media/CE48787148785A63
bash: echo: write error: No space left on device

when running $ df -h

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda7        90G   86G     0 100% /
udev            1.9G  4.0K  1.9G   1% /dev
tmpfs           781M  1.1M  780M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            2.0G  3.3M  2.0G   1% /run/shm
overflow        1.0M   16K 1008K   2% /tmp
/dev/sda2       230G  184G   46G  81% /media/CE48787148785A63
bash: echo: write error: No space left on device

after running disk free command with -k and -h flags. It is clear that My device has ample space to work on. If someone has resolved the same issue please help me.

I believe you are hitting the limit on your /dev/sda7 drive that isn't reserved. To see more about reserved space, please see:

https://unix.stackexchange.com/questions/7950/reserved-space-for-root-on-a-filesystem-why

To lower the amount of space reserved (looks like it is currently set at 2%), you can run the following command to lower it:

sudo tune2fs -m 1 /dev/sda7

Please note that the reserved space is there for a reason. This will cause issues later if you continue to use up more space.