I never installed Oracle on my system and don’t know why these directories kept being created, but I finally managed to stop them from reappearing. Here’s how it’s done.
First, head over to:
cd ~/oradiag_<username>/diag/clients/user_<username>/host_*/trace/
and then
head sqlnet.log
You should see an error message complaining about a directory not existing for r/w. For me, it was /usr/lib/log. I created the directory it was complaining about and deleted the oradiag_<username> directory, only to have it reappear later; however, the sqlnet.log file was now complaining about a different directory.
I repeated this process of creating directories a few times until the directory finally stopped appearing. In your case, the directories may be different, but here’s what solved it for me:
sudo mkdir /usr/lib/log/diag/clients
sudo chmod 777 /usr/lib/log/diag/clients
Only the clients directory needs to be 777, apparently.
Now just wipe out the oradiag_<username> directories wherever they currently appear. They shouldn’t pop up for you again.
In case you’re curious, here’s what finally ended up being written to that “missing” directory:
mike@mike-ubuntu:/usr/lib/log/diag/clients$ ll -a
total 8
drwxrwxrwx 2 root root 4096 2011-08-24 10:34 .
drwxr-xr-x 3 root root 4096 2011-08-24 10:34 ..
Brilliant.