Backup and Restore help
So for this class we're using CentOS. our instructor is going to run a script that'll nuke our systems... and we're expected to restore them using a tarball that we backed up on a server. I'm a little confused right now as to which directories i should keep and which ones i should exclude - mainly which ones I should exclude. Throughout the semester, we've done plenty of labs that have added users and groups, we've set up cronjobs, cups printing, etc...
So, my main concern is what are the files from a backed up tarball that, if restored onto a freshly reinstalled CentOS machine, will make it not work like it did before. So far, I think /etc/fstab and /etc/selinux should be -excluded from the initial tar... however I'm sure there's more.
And also, could someone tell me if I'm missing anything?