After searching this site, and reading the Ubuntu community documentation, I've decided to use a simple tar command such as
sudo tar -cvpzf serverbackupMMDDYYYY.tgz --exclude=/proc --exclude=/lost+found --exclude=/mnt --exclude=/sys --exclude=/media --exclude=/backups --exclude=/boot --exclude=/dev --exclude=/home -exclude=/tmp --exclude=serverbackupMMDDYYYY.tgz /
To backup my system. While researching how to backup my system it seemed some people recommended excluding /dev (as I'm doing above) and others warned that there could be problems doing that (but they didn't elaborate).
What are the pros and cons of including or excluding /dev in a backup?
I tested a full backup/restore and didn't run into any problems excluding /dev myself, but I also think I took more steps than necessary to restore. After inserting a non broken hard drive I reinstalled Ubuntu and then extracted the backup over the fresh install.
Some directories are irrelevant into a backup. For example:
They are created during the boot, and are related specific with your devices and/or your running processes.
While its irrelevant to backup or not - your kernel will recreate those directories when boot from restored backup - you probably will save a little time if you do not backup it.