I did a system upgrade of 3 PCs during the christmas holidays. 2 PCs were running OpenSUSE 12.3, one was still running OpenSUSE 12.1. I was really amazed by the upgrade process. Most things worked out of the box!
The server update was started via DVD. The other PCs were booted via PXE network boot. Here is the config PXE Linux config for the upgrade installation.
MENU LABEL ^upgrade system
APPEND install=nfs://192.168.xyz.xyz/srv/public/suse64 initrd=suse64/boot/x86_64/loader/initrd splash=silent upgrade=1 showopts
I need a while to figure out how to boot the upgrade system.
My old Mozilla Sync Server crashed during update. I didn’t fix it, because there is a new version out.
More info will follow.