It turned out that I was using the XFS filesystem for /usr, and in /etc/fstab I list the filesystem type as in /etc/fstab fixed this issue.
The upgrade warned me about the different architectures, and I proceeded just as I did in the virtual machine.
That way, if the cross-grade doesn't go well, you can quickly revert to the way the system was before you attempted the migration.
If you mirror the Fedora 8 Everything directory and the updates directory, you'll download more than you strictly need, but once you're in the throes of upgrading, the last thing you want is to wait for 600MB of data to download.
The DVD image, Fedora-8-x86_64-DVD.iso, is 3.7GB, the Fedora 8 Everything directory for x86_64 is 12GB, and the updates directory for x86_64 is 3.2GB, as of December 2007.
Creating files for the new local repositories allows you to use them in preference to the default and files.
Note that /yum-repo-mirrors should be a large enough partition to contain all this data: # cat f8#!
You'll waste even more resources if your new machine has 4GB or more of system memory, and you'll be forced to either not use some of it or run a 32-bit Physical Address Extension (PAE) kernel.
Cross-grading to the 64-bit variant of your Linux distribution can help you use your resources more wisely.
The warning was ominous, along the lines of "don't do this." I dismissed the warning; the upgrade proceeded, and I rebooted the virtual machine as normal.
Everything still seemed to work in the virtual machine after the cross-grade.
This happened to me with a Fedora Linux installation, and I finally decided to migrate.
Over the years, I've talked to Fedora enthusiasts and Red Hat employees at Linux conferences about doing a cross-grade to 64-bit. However, I like to reserve this approach for when a critical number of system disks fail at once and I have absolutely no other option.
I'm not sure what caused the problem with updating GRUB, but at least it presented no bar to booting. Fedora 8 has moved to Pulse Audio, and it wasn't working as it should.