Upgrading from Sarge to Etch

http://www.debian.org/releases/stable/i386/release-notes/ch-upgrading.en.html

backup /etc, /var/lib/dpkg and the output of dpkg --get-selections "*"

change /etc/apt/preferences

New /etc/apt/sources.list:
------------------
deb http://security.debian.org/ etch/updates main contrib non-free

deb ftp://ftp.nl.debian.org/debian etch main contrib non-free
deb-src ftp://ftp.nl.debian.org/debian etch main contrib non-free
------------------

aptitude -y -s -f --with-recommends dist-upgrade
shows how much free space you need

aptitude upgrade
does a minimal upgrade without removing the packages

aptitude install initrd-tools

aptitude install udev

aptitude install discover

make sure lvm2 is installed, as lvm 1 is incompatible, as are snapshot volumes, so they need to be removed from /etc/fstab and can safely be destroyed.

Also make sure dmsetup is installed.

If the machine exports NFS volumes, make sure the portmapper is listening to all ports (/etc/default/portmap)

Make sure the packages which were changed are running under the new configuration

Upgrade the Kernel:

apt-cache search linux-image-2.6- | grep -v transition

aptitude install linux-image-2.6-686

/etc/lilo.conf initrd configuration. use mkinitrd to create it if it isn't there allready. Check the existence of the files!
-----------------
image=/vmlinuz
        label=Linux
        read-only
        initrd=/initrd.img
#       restricted
#       alias=1

image=/vmlinuz.old
        label=LinuxOLD
        read-only
        optional
#       restricted
#       alias=2
-------------------

rerun lilo after editing lilo.conf

check mountpoints and exports - make sure nothing is accessing them before the next step, so make sure any servers using those mountpoints have unmounted them cleanly!

reboot

pray a bit

login

backup the mysql databases

aptitude dist-upgrade (nb make sure of free diskspace!)

to get the package signature checking mechanism:

apt-get install debian-keyring

apt-key add /usr/share/keyrings/debian-role-keys.gpg

aptitude update

in /etc/default/snmpd
change 
SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid'
to allow access from all hosts

/etc/X11/xdm/Xaccess there's some broadcast option set which I'm not sure yet if it's important.

make sure that in /etc/kernel-img.conf
do_bootloader = Yes
exists

check the raid arrays
mdadm --detail /dev/md0
(http://svn.debian.org/wsvn/pkg-mdadm/mdadm/trunk/debian/README.upgrading-2.5.3?op=file)