BTRFS with RAID1 cannot boot when removing drive

[Saint Germain <saintger@gmail.com>]

Hello,

I am experimenting with BTRFS and RAID1 on my Debian Wheezy (with
backported kernel 3.12-0.bpo.1-amd64) using a a motherboard with UEFI.

However I haven't managed to make the system boot when the removing the
first hard drive.

I have installed Debian with the following partition on the first hard
drive (no BTRFS subsystem):
/dev/sda1: for / (BTRFS)
/dev/sda2: for /home (BTRFS)
/dev/sda3: for swap

Then I added another drive for a RAID1 configuration (with btrfs
balance) and I installed grub on the second hard drive with
"grub-install /dev/sdb".

If I boot on sdb, it takes sda1 as the root filesystem
If I switched the cable, it always take the first hard drive as the
root filesystem (now sdb)
If I disconnect /dev/sda, the system doesn't boot with a message
saying that it hasn't found the UUID:

Scanning for BTRFS filesystems...
mount: mounting /dev/disk/by-uuid/c64fca2a-5700-4cca-abac-3a61f2f7486c on /root failed: Invalid argument

Can you tell me what I have done incorrectly ?
Is it because of UEFI ? If yes I haven't understood how I can correct
it in a simple way.

As extra question, I don't see also how I can configure the system to
get the correct swap in case of disk failure. Should I force both swap partition
to have the same UUID ?

Many thanks in advance !

****************************************************
Here are some outputs for info:

btrfs filesystem show
Label: none  uuid: 743d6b3b-71a7-4869-a0af-83549555284b
	Total devices 2 FS bytes used 27.96MB
	devid    1 size 897.98GB used 3.03GB path /dev/sda2
	devid    2 size 897.98GB used 3.03GB path /dev/sdb2

Label: none  uuid: c64fca2a-5700-4cca-abac-3a61f2f7486c
	Total devices 2 FS bytes used 3.85GB
	devid    1 size 27.94GB used 7.03GB path /dev/sda1
	devid    2 size 27.94GB used 7.03GB path /dev/sdb1

blkid 
/dev/sda1: UUID="c64fca2a-5700-4cca-abac-3a61f2f7486c" UUID_SUB="77ffad34-681c-4c43-9143-9b73da7d1ae3" TYPE="btrfs" 
/dev/sda3: UUID="469715b2-2fa3-4462-b6f5-62c04a60a4a2" TYPE="swap" 
/dev/sda2: UUID="743d6b3b-71a7-4869-a0af-83549555284b" UUID_SUB="744510f5-5bd5-4df4-b8c4-0fc1a853199a" TYPE="btrfs" 
/dev/sdb1: UUID="c64fca2a-5700-4cca-abac-3a61f2f7486c" UUID_SUB="2615fd98-f2ad-4e7b-84bc-0ee7f9770ca0" TYPE="btrfs" 
/dev/sdb2: UUID="743d6b3b-71a7-4869-a0af-83549555284b" UUID_SUB="8783a7b1-57ef-4bcc-ae7f-be20761e9a19" TYPE="btrfs" 
/dev/sdb3: UUID="56fbbe2f-7048-488f-b263-ab2eb000d1e1" TYPE="swap"

cat /etc/fstab
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
UUID=c64fca2a-5700-4cca-abac-3a61f2f7486c /               btrfs   defaults        0       1
UUID=743d6b3b-71a7-4869-a0af-83549555284b /home           btrfs   defaults        0       2
UUID=469715b2-2fa3-4462-b6f5-62c04a60a4a2 none            swap    sw              0       0

cat /boot/grub/grub.cfg 
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  load_env
fi
set default="0"
if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function load_video {
  insmod vbe
  insmod vga
  insmod video_bochs
  insmod video_cirrus
}

insmod part_msdos
insmod btrfs
set root='(hd1,msdos1)'
search --no-floppy --fs-uuid --set=root c64fca2a-5700-4cca-abac-3a61f2f7486c
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=640x480
  load_video
  insmod gfxterm
  insmod part_msdos
  insmod btrfs
  set root='(hd1,msdos1)'
  search --no-floppy --fs-uuid --set=root c64fca2a-5700-4cca-abac-3a61f2f7486c
  set locale_dir=($root)/boot/grub/locale
  set lang=fr_FR
  insmod gettext
fi
terminal_output gfxterm
set timeout=5
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_msdos
insmod btrfs
set root='(hd1,msdos1)'
search --no-floppy --fs-uuid --set=root c64fca2a-5700-4cca-abac-3a61f2f7486c
insmod png
if background_image /usr/share/images/desktop-base/joy-grub.png; then
  set color_normal=white/black
  set color_highlight=black/white
else
  set menu_color_normal=cyan/blue
  set menu_color_highlight=white/blue
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Debian GNU/Linux, with Linux 3.12-0.bpo.1-amd64' --class debian --class gnu-linux --class gnu --class os {
	load_video
	insmod gzio
	insmod part_msdos
	insmod btrfs
	set root='(hd1,msdos1)'
	search --no-floppy --fs-uuid --set=root c64fca2a-5700-4cca-abac-3a61f2f7486c
	echo	'Chargement de Linux 3.12-0.bpo.1-amd64 ...'
	linux	/boot/vmlinuz-3.12-0.bpo.1-amd64 root=UUID=c64fca2a-5700-4cca-abac-3a61f2f7486c ro  quiet
	echo	'Chargement du disque mémoire initial ...'
	initrd	/boot/initrd.img-3.12-0.bpo.1-amd64
}
menuentry 'Debian GNU/Linux, with Linux 3.12-0.bpo.1-amd64 (mode de dépannage)' --class debian --class gnu-linux --class gnu --class os {
	load_video
	insmod gzio
	insmod part_msdos
	insmod btrfs
	set root='(hd1,msdos1)'
	search --no-floppy --fs-uuid --set=root c64fca2a-5700-4cca-abac-3a61f2f7486c
	echo	'Chargement de Linux 3.12-0.bpo.1-amd64 ...'
	linux	/boot/vmlinuz-3.12-0.bpo.1-amd64 root=UUID=c64fca2a-5700-4cca-abac-3a61f2f7486c ro single 
	echo	'Chargement du disque mémoire initial ...'
	initrd	/boot/initrd.img-3.12-0.bpo.1-amd64
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###