I would suggest AUTOMATING looking at your own very old files and see if its necessary and remove them. This can done with two things. One writing a find command to look for very old files. and using this output (maybe pipe) to lograte script to archive files older than says 3 months and delete files older than 3 months in archive and send a mail to 1 day before deleting it. So that you can be sure you have not lost any important file. So in finally you would need the following commands to accomplish the above:
find , | , logrotate , mail, crontab
I am not going to spoon feed you. I have done this before has been quite successful with this and was later scrapped because we decided to go with nagios for monitoring as it was more tuned to do that kind of stuff in a corp server. I think if mail command is not already configured for you, you might find that the toughest rest should be straight forward. This all needs to done through bash scripting and putting that in cron job and to run every x days. Learn bash scripting, it will be very useful not only for this but to make your life easier with *nix. So use your favourite internet search engine and read about the above commands and bash scripting. And tie them together and test it. Once satisfied put to regular use. I assure it will be fun doing this. You will learn a lot if you haven't done this kinda before.
du -sh /to see where most of your space is being used. – xenoterracide♦ Sep 14 '10 at 21:33du -sh /*? – Stefan Sep 14 '10 at 22:32cd /and rundu -sh *and drill down... (you don't really have enough ram to store stuff in it) – xenoterracide♦ Sep 15 '10 at 3:13