To format or not to format

[oshunluvr]

Yes, IMO. Use btrfs.

On a simple install on a new computer with one storage device, you'd have a small EFI system partition, maybe a swap, and the rest a btrfs. For btrfs the *buntu installer silently puts root and home in separate subvolumes, @ and @home, which gives the same separation that root and home partitions do. With a typical computer with an SSD and a hard drive the second drive would be one big btrfs, to facilitate btrfs send/receive backups.

As for clean install versus upgrade in place, this forum has very divergent opinions. On one side you've got claydoh who has upgraded in place for "many years", and on the other you've got GreyGeek who rarely passes on the opportunity to urge "clean" installs^*. IMO it depends how much work a clean install needs to get it fully functional with software installed and configured, and settings changed. For me, it takes many days before everything is just right. I tend to do a clean install every so often, maybe every LTS, but sometimes hardware or software failures have encouraged the clean install. I'm trying to work up a clean Focal Fossa install, to discard accumulated cruft, but after a few long sessions I've still got a long way to go.

With btrfs, you can have "a bob each way"^† and try both. Snapshot, do the release upgrade, check it out, and if not ok go back to the snapshot in seconds, not the fraught full restore from backup that a non-snapshotting fs requires.

^* "clean" means a new home directory. IME it's been a good idea when KDE got a new major version, like 3 to 4 and 4 to plasma.

^†do Americans say "a dime each way" to have a small bet on each alternative?

I don't think I could have said it better myself

[bweinel]

I usually prefer doing a clean install here... It just cleans up any leftover cruft from the old installation. However, I always do it on a fresh SSD drive (...installed on a removable drive sled so I can make drive changes in seconds.). Once the new install is working to my satisfaction, I put my original SSD in on the second sled and copy over all my $HOME directory stuff from the previous installation. Bulletproof... and it also gives you a complete cold spare SSD which can sit on the shelf in case catastrophic issues occur down the road. (That's saved my bacon more than once.)

BTW: No issues to report yet on 20.04b. I just had some fun setting local DNS resolution with a static ip on the beta. The resolv.conf / netplan linkage in the beta image leaves a little to be desired in this area, but I suspect most folks use dhcp these days. YMMV

cheers
Bill

[mick.kde]

Thank you for your responses. I learned some things and have much to think about. Just what a guy needs for lockdown.

[Qqmike]

Back to my Post #8 where I said I do clean installs, often, actually, before doing the clean install, I zero-out the drive using dd. That's especially useful if you've got all sorts of stuff laying around your drive from beginning to end, or various partitions sitting here and there, GPT back-up data, or multiple ESPs, whatever. It doesn't hurt to do this with dd, although it does take some minutes. Some practitioners say it "freshens up" the drive, I suppose by activating the bits on the drive.