FreeBSD Upgrade: newbie messed up the zfs boot configuration (slightly)

[enno1]

Hey there,

today I decided to upgrade my FreeBSD System, so I started to read the docs and once stumbled upon the freebsd-upgrade command (just used pkg update before) I started to give it a try (without RTFM).

Everything seems to be installed fine - it's just that I have to select the correct ZFS root snapshot by pressing "8" during the boot menu. "default" seems to point to the wrong "snapshot" [1] (sorry if I'm using the wrong term here), so the question is how can I make
zfs zroot/ROOT/15.0-RELEASE_2025-12-08_185706 the zroot/ROOT/default ZROOT?

I could also delete the 15.0-RELEASE snapshot and restart the upgrade, but on the other hand the kernel seems to be upgraded and that would break all executables, so i would have to downgrade the kernel, too.

Kind regards

[1] If I boot that environment, all executables fail complaining about missing/wrong libc version .so.

 

[drsnx60]

# man bectl
.
.
bectl [-r beroot] activate [-t | -T] beName

activate [-t | -T] beName
Activate the given beName as the default boot filesystem. If the
-t flag is given, this takes effect only for the next boot. Flag
-T removes temporary boot once configuration. Without temporary
configuration, the next boot will use zfs dataset specified in
boot pool bootfs property.


is what I assume would solve you issue
never happend to me so never had chance to practice .

 

[enno1]

Thanks for your reply.

I also thought about just setting the filesystem/snapshot zroot/ROOT/15.0-RELEASE_2025-12-08_185706 as the default for booting, but I'm not sure if this is unnecessary "fragmenting" the ZFS filesystem list.

It's probably the right thing to do, because you have these kind of snapshots/filesystems after an update anyway, but I can not verify how it should look when all is done correctly.

That's why I decided - because of your input - to verify how a clean upgrade looks like on ZFS (by using a second system) and maybe then I decide that for me it will be the best to rollback the whole update.

Because up to now it always felt like a pleasure to use ZFS, I'm looking forward that this will work out just fine. Maybe I will ask another question, once I see how a cleanly upgraded FreeBSD ZFS looks like.