I have a FreeBSD 8.0 amd64 box w/ 1 ATA drive for system root and 4 SATA drives as a RAIDZ pool. The ATA drive isn't mirrored nor part of any pool, but also doesn't hold any valuable data (other then the system). How can I recover my zpool if this ATA drive fails for any reason, but assume my RAIDZ vdev SATA drives remain intact? Should I also use at least a mirror configuration for that?