[CentOS] upgrading from CentOS 7 to 8

Tue Oct 1 20:19:11 UTC 2019
Valeri Galtsev <galtsev at kicp.uchicago.edu>


On 2019-10-01 12:57, MAILIST wrote:
>> Your answer has nothing to do with the original question which is related
>> to upgrade method and not condition for reinstalling without loosing
>> data.
> 
> After 40 years of upgrading many different operating systems,
> Windows (from 3.1 to 10), CentOS 6 to 8, Ubuntu, Fedora, Red Hat,
> AT&T Unix, VAX VMS; I have never observed an upgrade from one major
> version to the next to work.  The last one I tried using their "upgrade
> process" was Ubuntu 18 to 19.  Didn't work.

I routinely upgrade FreeBSD. Last time it was 11.3 to 12.0. Always 
smooth. Maybe I'm just lucky...

Valeri

> 
> When a new major version of any o/s is released, I have found it best
> to save what application data I can, delete all partitions on the target
> boot disk, and then install from scratch.
> 
> I learned years ago to keep application data out of system directories,
> ideally on a separate drive that can be mounted on the new installation.
> Yes, you do loose your settings, but that's why it would be wise to stick
> with the defaults, if possible.  Yes, the database is always in a system
> directory by default, so that's why you do a dump before the upgrade.
> My "cheat-sheet" of things to do during an upgrade is about 10 pages long.
> 
> If you do have to restore from a backup, be sure you do not restore any
> system directories (like /etc/fstab).  I made this mistake, once!
> 
> System admins must learn to bite the bullet on this part of their job.
> 
> Todd Merriman
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> 

-- 
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Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
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