I've been running a production P3 machine with Ubuntu 7.10, Postfix and ISPconfig for the past year+ and would like to upgrade to Ubuntu 8.04 LTS. However, I'm having difficulty even doing updates while ISPconfig is running. In the past, my solution for updates was to reboot the server in single user mode, run apt-get from console. However this method takes down all 30+ domains that are hosted on the machine for an hour or two. Is there a better way to do routine updates?