On my server with Ubuntu 11.04 I run a web server and an irssi session within screen.
The server freezes after a while. When I try to access its web pages, it only says "Loading" before it timeouts. When trying to connect through SSH I get no response followed by a timeout.
However, ping is responding and the auto-op feature on irssi still works.
A reboot is the only way I have found that solves it.
What could be the problem? How can I log the performance and status of the system to get more info on what is going wrong?