I have an Ubuntu 8.04 LTS Server that we use as a web server. It's a standard LAMP stack and our site is set up in Drupal. This seems to work without a problem for weeks on end. Then, out of nowhere, the processor will lock up entirely. When it does the only choice I seem to have is to hard-reset the system.
Remote logins all become unavailable, and if I sit in front of the terminal I'm sometimes able to type in my username, but it never gets as far as asking me for the password. Because I can't get into the system I can't seem to isolate the process that's consuming all of the processor time. I'm wondering what logs I can review or what I can enable to get access to better information and track down a root cause. Ideally, if I can find out what's causing the problem I can prevent it from recurring.