Upgrade one LTS to another directly? Need some advice

[akand074]

I have a question.
It seems the majority of users recommend a clean install upgrade.
When I just searched the Community Documentation for this I was unable to find anything, or anything complete. The sign-posted front page did not lead me to a procedure. There are detaled instructions on doing a regular upgrade.

What is the procedure?

Eg: If /home is in a separate partition then you erase and re-install to the /root partition and remount the original /home.
OK. But what happens to all your applications?
What about listing all your existing apps before the install so you can remember what you've lost, if you do lose them? Can the inventory and re-installation be automated?
If you re-install the apps is there going to be any conflict with old apps files that are still in your original /home?
What about all your configurations in /etc?

How easy is this to do?

Well I always do it through a manual install using the installation disk. Basically you just select your '/' partition select to use it as EXT4 and format it and then choose to use your '/home' partition as ext4 WITHOUT formatting. Then let it install, it'll wipe your '/' partition and give you a clean install.

All of your applications will be gone! It'll be a clean, brand new install. But your data and config files are still there undamaged. So basically you just reinstall all your applications and when you run them you don't have to switch the settings back to what you want or re-add your bookmarks/addons or put your messenger chat info back in etc etc.

[YesWeCan]

But your data and config files are still there undamaged.

Thanks for explaining. It sounds like the user's configurations would be retained because they are within /home but the global configurations and any root home directory files will be wiped. For example, SSH config files, OpenVPN, Samba configs, mdadm, Grub file in /boot/grub, perhaps Java and database and webserver directories and anything else of that nature.

So there is some work required beforehand to identify what all the current applications are and what all the current global/root configuration files are.

I suppose one could back it all up first, then do a diff between the new and old / filesystems to see what needs copying back.

Is this your understanding?

[blauendonau]

Thanks for the information. But it doesn't completely answer my question: are upgrades safe in general to do? I'd be interested to hear perspectives on that. Once again, I'm interested in convenience and stability over than cutting-edge. It'd be nice to get away without having to reinstall all the repositories/programs.

In any case, I'm going to pop in the 10.04 LTS disk and overwrite the Maverick partition with it, if for no other reason, because it'll be supported a year longer. Thanks for the feedback so far, appreciated.

[snowpine]

Thanks for the information. But it doesn't completely answer my question: are upgrades safe in general to do? I'd be interested to hear perspectives on that.

Release upgrades are the official recommendation of ubuntu.com. Theoretically they should be smooth and safe. In practice of course no software is perfect, there are always bugs, and this applies to the update manager as well. You should always check the release notes and the forums before doing an upgrade. Furthermore, since hardware compatibility can change over time, I always recommend test-driving a Live CD of the target release, even if you are planning to upgrade-in-place. If there are any incompatibilities, it's better to know about them before you commit to the upgrade.

[blauendonau]

Okay, just finished the install of Lucid + about 340mb worth of updates and the nvidia drivers, works like a charm and it's nice to know it'll be supported for another full two years.

I'm concerned about upgrade safety because I've seen a LOT of people complain that the lastest upgrade caused their system to be unusable or even unbootable. Then again, Natty seems to have been less smooth than previous releases, so I don't know if this is an exception to the norm.

Anyways, I think I'll take snowpine's advice. There's no rush for me, Lucid will suit my needs perfectly for the next ~18 months and then I'll look into 12.04. Thanks everyone once again.