FreeBSD for noobs, note to self:
After install run:
# portsnap fetch
# portsnap extract
... otherwise most of your port installs will fail because dependent files are already newer versions.
Why this isn't handled after the installation automatically, is beyond me. Of course, so are many other things (like why port startup commands must be added to rc.d / rc.conf manually).
Oh, and note 2:
zpool will only allow "clean" unpartitioned disk to be added as spares (naturally). So, if for example, a previously failed installation already partitioned a disk for UFS or ZFS, you need to manually nuke the paritions.
Then you can easily add it as a spare with (adding disk ada3 to pool "zroot"):
# zpool add zroot ada3
