ZoL 0.6.3 introduced the ZFS event daemon, zed. It can execute scripts for every event ZFS generates (see
zpool events). A basic, but pretty useful example: Get a mail including a detailed report every a pool scrub finishes. Of course, anything you can script, you can do. The (small) drawback: At least the ZoL packages for Ubuntu ship without config files, examples and an upstart script for zed.
This leaves us with a working daemon, but it won't automatically start. Here's a basic upstart file to fix that.
# zed - the ZFS event daemon description "The ZFS event daemon" start on local-filesystems stop on runlevel [!2345] respawn expect daemon exec /sbin/zed
Put that bit in
/etc/init/zed.conf and you've got zed up and running after reboots.