There’s an interesting discussion on the blog of Debian and Ubuntu user, David Welton, about the relative merits of clean installing versus using dist-upgrade. The opinion of the poster and the commenters seems to be divided between whether or not upgrading, as opposed to doing a fresh install, is an advisable thing. I think Daniel Ruoso’s point that many dist-upgrade problems are likeley to be caused by non-supported packages, is a noteworthy one.
Having come to Ubuntu after having been a Windows user continually since v.3.1, my hunch was that I should favour clean installs over performing upgrades of existing systems (let’s face it, each Windows version generally required several clean installs during its own lifetime, without having to wait for the next official release). My first installation of Ubuntu was the 32-bit version of 6.06, Dapper Drake. I played with this on and off until Feisty was released, and despite my reservations about performing version upgrades as opposed to clean installations, I read the Ubuntu docs and decided to use dist-upgrade to update the system (via Edgy, of course, as dist-upgrade will not allow you to jump versions).
With it being on a spare machine, I was a bit cavalier and carried on using it while the upgrade took place. I was absolutely gob-smacked to see the application I was working with upgrade itself while I was using it. It temporarily used a different font set, then refreshed the window, and then politely advised me that it should be restarted (the app, not the OS) at a time convenient to me. Coming from Windows, this was radical stuff. It was like performing a 12,000 mile service, including tyre changes, while you’re doing 70mph on the motorway.
Despite having used the system while it was being upgraded, the process went well and Feisty ran sweetly (on an old P4 with 1GB RAM and 40GB HD). In fact, it went so well, and I liked Feisty so much that the experience convinced me to take the fateful step of shifting my life and work over to Linux on a permanent basis.
Sadly though, my next attempt at using dist-upgrade did not go so smoothly. When the time came to upgrade from Feisty to Gutsy (something I did mainly to get access to better wi-fi drivers) I again turned to dist-upgrade. Despite having all the latest updates installed on Feisty, and despite being sensible by leaving the machine alone while it upgraded, the resulting systems (one laptop and one desktop) were riddled with glitches and bugs, and sent me running for the ISO image. Gutsy was rather glitchy even after clean installs in my experience, although a couple of months into the life of the release the updates had taken care of the most irksome bugs.
After the Feisty to Gutsy experience, I ignored the dist-upgrade facility when moving to Hardy and performed clean installations instead. It would be nice to be able to rely on dist-upgrade and it would be great not to have to re-configure your machine manually after each version install, but the facility just seems too unreliable. On the upside, I can honestly say that I can build an Ubuntu workstation from scratch, import my data, and install 90% plus of the apps, utilities and other stuff I need, in around three to four hours or so. Windows upgrades used to be a major PITA. It always seemed to take the better part of a day to get a useable system (downloading huge service packs and updates, feeding application suite CDs to the drive and typing in CD-key after CD-key, hunting around for all those 3rd party utilities you’d installed, etc.) and the better part of a week a week to cross the ‘t’s and dot the ‘i’s. Ubuntu takes a few hours for the fundamental system, applications and major utilities (thanks to the wonderful synaptic), and I get most of the fine tuning done within a day, with one or two things I overlook being taken care of on day 2. Of course, the odd thing crops up over the following week or two, but Synaptic generally takes care of it within a few moments. It’s wonderful stuff! But I digress…