We had a problem where a server wasn’t allowing us to upload any more files using our web application’s interface. This was due to an enormous “error.log.1.txt” in “/var/log/apache2/” caused by setting our log level to warnings rather than errors. Thanks to Josh at blindhog.net I could run a command and quickly find directories over 1GB in size:
du -h / | grep ^[0-9.]*G
This quickly showed up our 12GB log file..