On Sat, Apr 30, 2011 at 3:48 PM, Steven J. Yellin
<[log in to unmask]> wrote:
>    Here's what I'd try if I were doing such an upgrade.  Others can judge
> whether it needs modification, or whether a disk install from .iso files is
> likely to work with SL6:

Folks, I've been pulling such stunts since RedHat 4.2. There are some
helpful rules.

* Do it on a test box first.
* Bring the test box up to the *LAST* minor release of the older OS,
in this case SL 5.5.
* Never increment more than one major OS upgrade at a time. (Doing 3.x
to 6.x would be insane.)
* Prepare for big problems if you're using badly organized,
out-of-band components. Locally compiled glibc, NVidia drivers,
manually installed kernels and mkinitrd that are not under RPM
management are all startingly risky.
* Eliminate all components that are not under yum management from the
main repository.
* Update the '*-release" packages first.
* Pray.
* Be ready for manual overrides and scripting of components with odd
namechanges and dependencies. gcc4x, for example, has had several
major package name changes that cannot be resolved with a mere 'yum
update'. And components like 'eclipse' have changed package names
between major releases, requiring customized management with the
installation media *do* have.

Frankly, I find it easier to merge the CD or DVD contents into a local
yum repository and use the small bootable installation media or PXE to
network boot and point to *that*, instead of swapping CD's or DVD's.
This also allows me to include kernel updates that may be critical, or
out-of-band components such as subverson or rsync or lftp mock that I
really want the RPMforge versons of.



> Add to the end of /boot/grub/grub.conf lines
>
> title SL6 Installation
>        root (hd0,0)
>        kernel /vmlinuz
>        initrd /initrd.img
>
> except "(hd0,0)" should be replaced by what you see for other grub entries,
> and I've assumed you have a boot partition.
>
> Reboot your machine, selecting in grub "SL6 Installation", and do a disk
> installation from the SL6Install directory of the partition you decided to
> preserve.  You can alternatively install over the internet instead of from
> your own disk.

It needn't be local if you can use PXE or the 'bootinstall' iso's, at
http://ftp.scientificlinux.org/linux/scientific/6.0/x86_64/iso/SL-60-x86_64-2011-03-03-boot.iso.
Making sure that the PXE kernel and OS support your existing network
hardware used to be more difficult, but has gotten far easier, so it's
almost always workable ot use for an update procedure.