So, right out of the gate, I'll admit it: I did a yum-based upgrade. The Fedora Project does not recommend this method, so unless you're really comfortable with the internals of the distribution, if you're upgrading then you should probably stick with the official FedUp tool. Having said that, I do have quite a bit of faith in Btrfs snapshots and my own ability to pass "rootflags=subvol=fc21_working" to the kernel during boot. In any event, the process worked fine, and the recovery tricks weren't necessary.
There are several changes in the workstation version, and even more in the Cloud and Server versions for that matter. The following, however, leaped out at me immediately (on a ThinkPad X1 Carbon gen 2, for those interested):
- Kernel 4.0.4
- This change isn't as intimidating as it seems. Mostly, this is just an incremental change, and could just as easily have been version 3.20 .
- The biggest change here is that the code necessary to support reboot-free kernel patches (available for some time with third-party tools) is now available in the mainline kernel. The functionality isn't readily exposed in workstation versions, so don't expect it to Just Work™, but anybody feeling brave can try it out with kGraft or Kpatch.
- Yes, for those of you who don't follow the HA GNU/Linux server world- you read that correctly. Linux has been able to do reboot-free kernel patches for some time with third-party tools. Kernel 4 just brings that into the standard kernel tree. Bet you don't hear MS or Apple talking about that one in their product demos, eh?
- Faster startup
- My boot, from power-on to GDM login dialog, was already about five seconds (not including GRUB menu timeout) with Fedora 21, courtesy of a good SSD. Fedora 22 shaved about one second off of that.
- Yum is deprecated, long live DNF!
- Yes, you read that one correctly, too. Good ole' yum is still around if you really want it, but it's been officially deprecated in favor of a new tool, dnf. DNF has virtually complete syntax compatibility with Yum, but has noticeably more zip-zoom, particularly for complex dependency resolution. There's even a new version of yumex (which retains the name, oddly enough) particularly for DNF.
- Using libinput by default, instead of discrete X.org drivers
- Many users probably wouldn't notice this at all. As I have a Synpatics trackpad, however, the initial trackpad behavior was a bit odd. The tracking and acceleration were different, but that was a quick adjustment. My two-finger right-click was also gone (not sure if that's libinput or Gnome 3.16), but it was quickly restored with dconf editor.
- Notifications are much nicer
- This is probably more Gnome 3.16 than anything Fedora-specific, but it's nice. Any notifications now show up briefly under the clock, and I can dismiss them completely, or they'll vanish on their own, and clicking on the clock shows a list of any notifications that haven't been dismissed.
So, the summary: going from Fedora 21 to Fedora 22 was a nice series of small improvements that, together, add up to a rather pleasant experience. The upgrade was reasonably painless, and so far all looks well. My next projects will be to mess around with the integrated Docker functionality, and to get reboot-free kernel patches working with kpatch.
Also worth noting: I was a devoted openSUSE user for several years, mostly courtesy of Yast. Fedora's system-config-* tools, while not quite a drop-in replacement, work well enough that, in tandem with the more widespread software support, I think Fedora is now my distro of choice.