I couldn't update my OpenIndiana box today because I'd run out of space in / and /var. It was actually two problems. Problem 1 was I had clean up some very annoying snapshots (which I created, so I'm the annoying one), which I found with:
zfs list -H -t snapshot -o name -S creation -d1 rpool/ROOT/openindiana-2020:12:27/var
zfs list -H -t snapshot -o name -S creation -d1 rpool/ROOT/openindiana-2020:12:27
I think there may be an easier way to clean this up but I ended up doing /var and then /, using this:
zfs list -H -t snapshot -o name -S creation -d1 rpool/ROOT/openindiana-2020:12:27/var | tail -16 | xargs -n 1 zfs destroy -r
zfs list -H -t snapshot -o name -S creation -d1 rpool/ROOT/openindiana-2020:12:27 | tail -16 | xargs -n 1 zfs destroy -r
(I specialize in long commands lines.)
This took me from 95% full to 23% full in /.
Nice.
/var wasn't completely fixed though, so I kept looking.
The second one was cause by the gigantic /var/pkg/publisher. A bit of research turned up the following gem:
pkg set-property flush-content-cache-on-success true
And then, now that I had at least some space free in / and /var, proceeded to run, and at the end, you can see it cleaning up the cache directories. Also nice.