gmirror on freebsd 9.3

### steps how to create
# load freebsd 9.3 in single-user mode (2)

gmirror label -vb round-robin boot /dev/da0p1
gmirror label -vb round-robin root /dev/da0p2
gmirror label -vb round-robin swap /dev/da0p3
gmirror load

mount /dev/mirror/root /mnt
echo 'geom_mirror_load="YES"' >> /mnt/boot/loader.conf
ee /mnt/etc/fstab
```
# Device	Mountpoint	FStype	Options	Dump	Pass#
/dev/mirror/root	/		ufs	rw	1	1
/dev/mirror/swap	none		swap	sw	0	0
```
reboot

### steps how to add new da1
# load freebsd 9.3 in single-user mode (2)

gpart backup da0 > da0.gpt
su
gpart restore -F /dev/da1 < da0.gpt or gpart backup da0 | grart restore /dev/da1
gpart show
gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 da1
gmirror insert boot /dev/da1p1
gmirror insert root /dev/da1p2
gmirror insert swap /dev/da1p3

### steps how to fix degraded da1
# shows disk serial number
geom disk list 
poweroff
# replase disk and boot in single user mode
gpart backup da0 > da0.gpt
su
gpart restore -F /dev/da1 < da0.gpt or gpart backup da0 | grart restore /dev/da1
gpart show
gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 da1

gmirror forget root
gmirror forget boot
gmirror forget swap

gmirror insert boot /dev/da1p1
gmirror insert root /dev/da1p2
gmirror insert swap /dev/da1p3

gmirror status

#gpart show
```
=>      34  16777149  da0  GPT  (8.0G)
        34       128    1  freebsd-boot  (64k)
       162  15935360    2  freebsd-ufs  (7.6G)
  15935522    837632    3  freebsd-swap  (409M)
  16773154      4029       - free -  (2M)
```