Backup question

[CS DBA]

Hi All;

I have an rsync script to backup my entire system each time before I run 
updates, as versions come & go I try and keep up with which top level 
directories to backup knowing that some like /proc are virtual...

Here's my question:  If I simply backup all directories (including ones 
like /proc & /media, etc) will the following work, or do I need to care 
about specifically excluding the virtual directories?


1) run the rsync backup of ALL directories in /

2) boot to a problem (say a boot to a blank screen)

3) boot into single user mode

4) run the rsync based restore (restoring everything from step 1)

5) reboot into the previous system state


Thanks in advance