For a while, I've had an issue whereby it takes up to 5 minutes from the moment I enter my password in Lightdm's login screen until I can do anything with my computer. That's on Ubuntu 12.04.
During that time, I see there is disk activity, but I'm not sure how to figure out what's causing it and whether that is the real cause.
I've played around with Bootchart unsuccessfully. Any ideas on what the best way to debug this issue is?
What I would try is to press Alt-Ctrl-F1 to switch to a text console, log in there and run top in the console. Then switch to the login screen again using Alt-Ctrl-F7, enter your login/password and while it tries to log you in switch back to the text console to see if you can spot any processes which cause the problem.
To see what processes are accessing the disk run:
sudo iotop -o
To stop the output disappearing after each access and to make the disk I/O cumulative (more useful in my opinion) run:
sudo iotop -oa
Play with the options (iotop -h) as required.
As I recall iotop needs to be installed with:
sudo apt-get install iotop.
