Re: [HELP] open_ctree failed when mounting RAID1

Jussi Kansanen
2022-06-02T12:49:42Z

On 5/31/22 22:50, Lucas Rückert wrote:
> Hi,
>
> i run two HHD's(sda;sdb) in RAID1.
>
> Kernel: 4.9
>
> Distro: Linux odroid 4.9.277-83 #1 SMP PREEMPT Mon Feb 28 15:16:26 UTC
> 2022 aarch64 aarch64 aarch64 GNU/Linux
>
> btrfs-progs: 5.4.1
>
> I created the filesystem with:
>
> mkfs.btrfs -d raid1 -m raid1 -L somelable -f /dev/sda /dev/sdb
>
>
> And added it to my fstab:
>
> UUID=<uuid>        /mnt/somefolder     btrfs compress=zstd   0       2
>
>
> When running:
>
> mount -a
>
> i get an error:
>
> mount: /mnt/backup: wrong fs type, bad option, bad superblock on
> /dev/sda, missing codepage or helper program, or other error.
>
>
> and dmesg reports:
>
> BTRFS error (device sdb): open_ctree failed
>
>
>
> Yours sincerely
>
> Lucas
>

Hi Lucas,

Invalid mount options can be reported as "BTRFS error (device sdb): open_ctree
failed". The reason for the error is that your kernel version doesn't support
zstd. 4.14 kernel added support for zstd or 5.1 if you want to set zstd
compression levels by mount option.

-Jussi Kansanen