root@cs0:~# head -1 /etc/devd/zfs.conf # $FreeBSD: releng/10.2/etc/devd/zfs.conf 272693 2014-10-07 13:30:15Z avg $ root@cs0:~# freebsd-version -ku 10.3-RELEASE-p11 10.3-RELEASE-p12 (I'm constantly upgrading system through svn sources, so you can see releng/10.2 in config because this file wasn't changed in 10.3) And I see respective log lines twice - one for the message itself and one for "executing ...": # fgrep ZFS /var/log/messages.13 Aug 10 19:56:59 cs0 devd: Executing 'logger -p kern.notice -t ZFS 'vdev state changed, pool_guid=3861546974548989537 vdev_guid=688554190753491733'' Aug 10 19:56:59 cs0 ZFS: vdev state changed, pool_guid=3861546974548989537 vdev_guid=688554190753491733 Aug 10 19:57:00 cs0 devd: Executing 'logger -p kern.notice -t ZFS 'vdev state changed, pool_guid=3861546974548989537 vdev_guid=688554190753491733'' Aug 10 19:57:00 cs0 ZFS: vdev state changed, pool_guid=3861546974548989537 vdev_guid=688554190753491733