Disks are cheap, so I'm buying a new disk for my server, copying all my
existing partitions to it (actually, I'll use dump and restore, which also
lets me do a "fire drill" on my backups). I'll then pull out the original
drive, boot from the new drive, and upgrade that. If anything bad happens,
I'll have the old drive to fall back to. Once the upgrade is done, I'll
mount the old disk read-only and diff the parts of the two systems that
I've customized (eg. /etc, /var, and /home) and figure out what
customizations failed to get migrated. I can also query the old RPM
database if needed to see where I got 3rd party packages. (I tend to stay
on the bleeding edge for things like SpamAssassin, getting the RPM from
upstream.)
