Re: RHEL 3->4: Upgrade or Fresh Install?

[dsavage peaknet net]

On Fri, 2005-03-04 at 08:38 -0500, Tim Evans wrote:
> RedHat's official install manual is kinda stern about recommending fresh
> installs rather than upgrading RHEL Version 3 to Version 4.
>
> What has been the list's experience?
>

Tim,

Given the major changes between RHEL3 and RHEL4 -- the 2.4->2.6 kernel, a
totally rewritten SCSI subsystem with all new drivers, SELinux (!),
support for >1T filesystems, yada yada yada -- there are just too many
possible ways to for an upgrade to fail, both obvious and hidden.

I dd'd my RHEL3 OS to image files on a separate drive, then did a fresh
install on the RHEL hard drive. Once it was up and running, I mounted the
old OS images and I'm manually migrating over everything I need to keep.
If, RHEL4 wouldn't install on my hardware for any reason, I could always
use that dd image to do a rapid bare metal restoration of RHEL3. That was
almost necessary when I encountered a grub stage2 failure heading into
Firstboot. Fortunately "linux rescue" allowed me to manually run
'grub-install /dev/i2o/hda' and save the day. (See Bugzilla #149184)

-- Doc
Robert G. (Doc) Savage, BSE(EE), CISSP, RHCE | Fairview Heights, IL
RHEL4/ES on Tyan S2468UGN w/3G, dual Athlon MP 2800+, 1.1T RAID5
"Perfection is the enemy of good enough."
                         -- Admiral of the Fleet Sergei G. Gorshkov