Upgrade vs Reinstall

[Paul Howarth]

Sean O Sullivan wrote:
> Tim Holmes wrote:
> 
>> Good Morning All!!!
>>
>> As we look toward the end of the academic year, I am beginning the
>> process of planning the IT projects for the summer.  One of the major
>> projects that I have in mind is to convert all of our FC2 boxes to FC3
>> -- I have about 6 FC2 servers in various roles around the school.  What
>> I am wondering is if there is a proper upgrade path, or if it is better
>> to back up the data and start over from scratch?
>>
>> If a RELIABLE upgrade path is available, can someone please point me to
>> the docs etc (since this would be the first Linux upgrade that I have
>> done, a step by step cook book style doc would be real helpful)
>>
>>  
>>
> I did similar upgrade from FC2 => 3, on various servers, it was a case 
> of inserting FC3 cd, booting off cd, and then when anaconda loads gives 
> you choice to upgrade.
> It took about 1-1.5 hours to do it, and afterwards all worked without 
> problems, there is small issue with apache I believe, but once you 
> update via your package manager it should be resolved.

I've done lots of upgrades in the past and would have few concerns about 
doing it again. It's less hassle than backing off all your data and 
doing a really clean install, but the end result is usually *slightly* 
different from a fresh install. For instance, a system upgraded from FC1 
will not have SElinux enabled by default, whereas a fresh install will have.

The amount of time the upgrade takes will depend on your hardware and 
how many packages are installed. On modern hardware, it could be as 
quick as half an hour for anaconda to do its stuff. I'd definitely go 
with anaconda rather than yum/apt upgrade routes as anaconda "knows" 
about various things it needs to do to upgrade specific releases.

Once the upgrade is done, you should perform some post-install changes.

First of all, install all the update packages (there are usually some 
updates posted in the first few days after a Fedora release, and 
currently there are around a gigabyte of available updates for FC3).

Next, look in /root/upgrade.log. This will tell you about packages with 
dependency issues (you may need to update them from external repos) and 
also about packages with configuration file changes where a .rpmsave or 
.rpmnew file has been created. You'll need to merge your original 
configuration files with those from the updated packages. Many packages 
will have unchanged config files, but you'll almost certainly need to 
merge in changes for httpd, samba and squid if you use them.

Finally, you can try running "rpm -qa --last". This will show you the 
packages installed, in reverse order of installation time. Recent 
versions of rpm will even show you when the packages were installed. The 
packages at the end of this list may be deprecated (not updated) and 
might want to remove them.

If you're going to do all this in the summer, you should also consider 
upgrading to FC4 (due to be released 6th June). That'll give you another 
6 months before your systems are end-of-lifed again.

Paul.