I want to get Centos 5 on my notebook, at minimal risk.
I want to install it on a clean drive, make sure it 'works', the delete everything but /home (which is on a separate partition) from the Centos 4 drive and copy the Centos 5 over.
Any 'caviats'? I would first tar up the Centos 4 stuff before putting my foot into it.
To what extent do I need to have the same drive layouts? Is it enough that /boot and / are consistant (ie each is in its own partition). I am working with /home in a separate partition.
I would make 2 tar backups, 1 of /home and one of everything else. If something doesn't work out in your install, you can repartition the drive, put all of your files back in place, and reinstall your boot loader and be back in business with your previous setup.
I might even prefer to let it reformat the whole drive, and restore /home from archive just in case there were any different filesystem options used between the two different CentOS versions.
Barry