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Old 2012-03-05, 20:04   #10
xilman's Avatar
May 2003
Down not across

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Originally Posted by ldesnogu View Post
I have always found the thought of upgrading frightening, whatever the OS is. No upgrade will leave the system in a clean state.
Been there, done that, just come out of a ten-day nightmare upgrading a pair of mission-critical systems. The most time-consuming portion was migrating >250GB in several million files from one 1TB USB disk to another so that BackupPC could continue to work properly. Have you any idea how long dumping, transferring and extracting that number of files takes? Once extracted, have you ever tried setting user and group ownerships? After having done that, do you know how long it takes to restore their SELinux contexts? It took me the best part of a week. Did you know that Fedora 16 and the latest Samba have a shared bug such that back-ups via BackupPC fail miserably for Windoze clients? That's why the backup sub-system had to be migrated from the machine upgraded from F14 to F16 to another which had only reached as far as F15.

Even attempting an upgrade was fraught. I found out too late that pre-upgrade on a Fedora system doesn't work if the system boots from a mirrored disk. All RAID variants just plain don't work and you have to download an ISO image, burn it and then upgrade from that.

A few weeks ago I tried to upgrade another F14 machine. That one failed even to boot after the bootloader had been upgraded from grub to grub2. I gave up and installed OpenBSD instead. Luckily it was a pure compute server and so had very little state worth preserving.

This post more properly belongs in the Unhappy Me thread, IMAO.

Originally Posted by ldesnogu View Post
I just reinstall, which doesn't mean reformatting. Of course that also means you need to have your /home directory in a separate partition or disk from / directory. If you have such a setup, reinstalling is no harder and no longer than upgrading (just did it yesterday going from Fedora 12 to Mint Linux). If you don't, then backup your home (you should do that anyway before upgrading) and install your new OS using a separate partition for /home.
Not quite true, in my experience. For days, possibly months, after a reinstall I find that various obscure configuration needs to be replicated. Stuff like restoring /etc/hosts from backups usually shows up earlier than later. Other stuff, like performance tweaks for obscure services, can take ages to find and replace.
Originally Posted by ldesnogu View Post
Another nice trick is to create a new user so that you get correct default configuration files and then transfer what you need from your old account
Useful tip. I've used the process on occasion though usually in desparation.


Last fiddled with by xilman on 2012-03-05 at 20:05
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