Arch Linux

Moviuro

Member

Registered: 2012-06-03

Posts: 74

[solved] BTRFS Raid1 over LUKS: can't boot

Hi all!

Until yesterday, I never had a machine with two drives so I experimented with BTRFS' RAID capabilities and now use the following layout on my new machine:

• /dev/sdc1 is a 512MB vfat /boot on SSD

• /dev/sda1 and /dev/sdb1 are both 2TB LUKS containers; say that they are mapped to /dev/mapper/a and /dev/mapper/b respectively

• BTRFS is RAID1 over /dev/mapper/a and /dev/mapper/b (both data and metadata)

• There are 3 subvolumes on BTRFS: __active/root, __active/home and __active/var (resp. /, /home, /var)

I use the systemd HOOK in mkinitcpio.conf, along with sd-encrypt and sd-vconsole (I'm using the French keymap). This works just fine in a single drive setup, but on my new multiple-drive setup, it fails with the error:

btrfs: open_ctree failed

In /etc/crypttab.initramfs, I have one line per drive (a and b, see above for the mapping).

I tried using multiple cryptdevice= on the kernel line to no avail.
I tried using a custom .mount service for /, to no avail.

Now I'm all out of ideas...

Also note: I only have access to my machine from 4pm UTC to 10pm UTC. I'm also available on IRC at the same time. I'll try to answer any possible question in the meantime, though answers may not be precise enough!

Cheers!

EDIT1: Of course, my btrfs formatting is perfectly fine: if I boot on the live ISO, I can successfully run:

# cryptsetup luksOpen /dev/sda1 a
# cryptsetup luksOpen /dev/sdb1 b
# mount /dev/mapper/a /mnt

EDIT2: Also, I'm using UEFI with systemd-boot: no crazy GRUB or whatnot.

SOLUTION: I actually typo-ed my kernel command line, ending with some unfindable devices. The boot process was far from verbose enough, though, which was really a pain.

Last edited by Moviuro (2016-07-26 17:54:52)

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bspwm, BTRFS over LUKS
Archlinux a lot, FreeBSD more and more...
Murphy's rule: The day you need a backup, you tell yourself you should have created some.