Debian: is possible to boot with a btrfs raid1 degraded?

Question

I have setup a Debian vm to boot with a RAID1 btrfs made with two encrypted devices. I had setup the vm like this

/etc/default/grub

GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_ENABLE_CRYPTODISK=y
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX="cryptdevice=UUID=b5259968-2f96-4a45-87bf-c658f6d0f55d:luksvda4 cryptdevice=UUID=6aae0722-1fc0-49d1-85d7-ca5668b06683:luksvdb4 rootflags=degraded"
GRUB_TERMINAL="console"

This is the /etc/fstab

LABEL=ROOT  /               btrfs   defaults,degraded   0       1
LABEL=BOOT  /boot           ext4    defaults            0       2
LABEL=SWAP  none            swap    sw                  0       0

this is the /etc/crypttab

# <target name> <source device>     <key file>  <options>
luksvda4 UUID=b5259968-2f96-4a45-87bf-c658f6d0f55d none luks
luksvdb4 UUID=6aae0722-1fc0-49d1-85d7-ca5668b06683 none luks

And finally the disk configuration

fdisk -l /dev/vda

/dev/vda1       48    65583    65536  32M BIOS boot
/dev/vda2    65584  2162735  2097152   1G Linux RAID
/dev/vda3  2162736  8454191  6291456   3G Linux swap
/dev/vda4  8454192 62914526 54460335  26G Linux filesystem


fdisk -l /dev/vdb

/dev/vdb1       48    65583    65536  32M BIOS boot
/dev/vdb2    65584  2162735  2097152   1G Linux RAID
/dev/vdb3  2162736  8454191  6291456   3G Linux swap
/dev/vdb4  8454192 62914526 54460335  26G Linux filesystem

I use the classical mdadm ext4, but also btrfs on boot partition(unencrypted of course) works fine. The system boot, no problem after asking the two password for the two luks devices. But when I remove the firs disk(simulating a fault) go to the initramfs console and I have to mount the disk manually(sic!), this not happen with the same configuration on Slackware. The question is: is possible to force Debian to boot when one of the two disk is not available?

Answer 1

Too easy: on /etc/fstab I put the nofail option, and boot without problem even with one disk

LABEL=ROOT  /               btrfs   defaults,degraded,nofail   0       1
LABEL=BOOT  /boot           ext4    defaults,nofail            0       2
LABEL=SWAP  none            swap    sw                         0       0