The notes client dumps a lot of different kinds of logging in a logs folder. At times your client crashes, or you do a memory dump from the OSGI console, your creating a large file in the logs folder. In my case, each one is about 1gb and I’m saving 80GB of hard drive space when I delete these files.
Check your log directory and do your spring cleaning.
In my example, I’m working with IBM Notes Client / Designer 8.5.3. You can measure someones XPages Bestiality by viewing the size of their log file.