Main partition nearly full, can't find the source
One of my servers in recent days has been using up more and more of the root partition, and not sure why
This happened once before, there were a lot of core files in /usr/local/apache for some reason, removed those and everything went back to normal. So, I checked for the same thing today but nothing

So I ran:
du -m --max-depth=1
This showed the problem most likely in the /usr directory just like last time, but after looking at most directories in there I can't seem to find what might be taking up so much extra space.
Any ideas or places to look?