How to merge lv_home and lv_root

 unmount and remove 2nd volume
# umount /dev/vg_groupname/lv_volumename
# lvremove /dev/vg_groupname/lv_volumename

extend 1st logical volume
# lvextend -l +100%FREE /dev/lv_groupname/lv_root

extend file system
# resize2fs /dev/vg_groupname/lv_root