Ubuntu – Root filling up although it should have some space

disk-usagefilesystem

This has been perplexing me for some time. I'm on Ubuntu 11.04. My root partition is filling up and I can't figure out what's causing it. Even stranger, when I run df -h, this is the output:

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2             9.2G  8.8G     0 100% /

As you see, there should be about 400 MB free, but Avail shows 0. What could be causing this? I've even uninstalled some programs to free the space and it fills up again. Suggestions on how to find out which, if any, files are filling up the space are also welcome.

Best Answer

A first shot: High traffic in an error log. I guess if you would download videos, you would know it. :) 

 sudo du -sh /var/log
  • -s is summary
  • -h is human readable (k, M, G, T) suffix

For me it is 20M, and beside the log-directory, there is a cache for the installations. Use 

 apt-get clean

If this is your problem.

Of course, you should check /home if it is in your root partition.

If you have to search big files iteratively, I can suggest a series of commands, which can be repeated and is pretty fast after the first initial step:

  • You start at a suspicious directory at top level
  • Then you search all subdirs and files for their size, and sort numerically: 

sudo du -s /var/* | sort -n 
0   /var/crash
4   /var/www
44  /var/games
124 /var/run
2306    /var/tmp
18538   /var/log
251876  /var/cache
1053231 /var/lib
  • I stripped the example, to keep it short. So we see, that the bigest subdir is /var/lib, and repeat the step for /var/lib. Now the search is much faster, because the computated results are somehow cached:

sudo du -s /var/lib/* | sort -n 
78116   /var/lib/apt-xapian-index
104580  /var/lib/dpkg
680503  /var/lib/postgresql

and so on. Follow the biggest dirs to find the bigger files. You can't use -sh here, because sorting numerically does not work with the k/M/G/T for kilobyte and so on.

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