I was having a difficult time when first switched over to Linux looking for the disk size reporting tools as convenient and fast as my GaugeIt (under Windoze). I tried every single tool that I could possibly found. My choice was durep, and I'm still using it. Details at the end of the file.
There is one kind of tool that I didn't find — disk space active watcher. There has been times that I was living on the edge — all my disks were nearly full, so I have to keep a keen eye on them, to take some actions before it is too late. You know when all the disks are full, the only option you have is to delete. If I can get some early signals, then I might avoid deleting anything.
Since I didn't find such tools, I wrote one myself. Hence the dfw. It inherits my philosophy — use as less resource as possible, i.e., the code base and package size should be as small as possible, it should consume as little CPU power as possible and should run as fast as possible.
Ubuntu (Debian) has native package for durep:
http://packages.ubuntulinux.org/dapper/utils/durep
As early as Dec 2002, the package contains an cron script that creates daily usage reports and stores them for about one week. So you can look back over the past week to try and isolate where changes in disk space are happening. It also takes a snapshot once a month for longer term changes, so you can look back up to one year.
I guess this feature is especially good for people who are maintaining many computers.
Further, you can try it's latest version - version 0.9 released Sept 2004. It' a complete rewrite new version. Web reports are generated via a CGI script, which is far faster and less space intensive than the old method.