Something
public text v1 · immutable# pvmove /dev/hda5 /dev/hdb1
FATAL: Module dm_mirror not found.
/sbin/modprobe failed: 1
mirror: Required device-mapper target(s) not detected in your kernel
gentOo sputnick # grep CONFIG_DM_MIRROR /usr/src/linux/.config
CONFIG_DM_MIRROR=y