Very long time since last update - upgrade or reinstall?

[dyqik]

I have two gentoo systems (one laptop and one desktop) that I have deliberately avoided updating for the past 1 and three quarter years while I used them to write my PhD thesis (don't ask why it took so long). I've now finished, submitted and been examined, so it's time to get these machines up to date.

Does anyone have any opinions on whether it would be better to start again from scratch or do a massive emerge -uD world? I have had a few issues getting things to work before with six month gaps between updates, and it's probably a good time to get rid of the cruft on these machines anyway. Both systems run reasonably complete desktops and scientific stuff, so reinstalling could take a good while.

[bur]

I would just do an emerge -avuD world (or system for a start) as I think there's no need for a complete reinstall, it will only give you more work for configuring everything and so on. And the outcome should be the same anyway.

I also had a Gentoo-system that I hadn't updated since about summer 05 and the "emerge -avuD system" I did yesterday took nowhere as long as I expected, about 40 packages needed to be updated (gcc and glibc being the biggest ones) which finished in a couple hours. Updating world will take much longer though I fear as KDE will be updated... But as I have a very minimalistic system (only the minimum KDE packages plus KEdit, Konsole, etc and Firefox) it shouldn't take too long.

Anyway, I see nothing that would speak against updating by emerge but there are disadvanteges when reinstalling. So simply go with emerge -avuD world.

Be sure to check the USE-Flags for each package before merging, there are some new ones. For example glibc is compiled twice now (in most cases unnecessary) when "nptlonly" isn't set since version 2.3.4 and there were some other new flags for my packages.