On Tue, Sep 28, 2021 at 1:59 PM Chris Murphy [off-list ref] wrote:

On Tue, Sep 28, 2021 at 2:53 PM Matt Zagrabelny [off-list ref] wrote:

quoted

Greetings btrfs folks,

I am attempting to mount a filesystem on a (likely) failing disk:

$ mount /var/local/media
mount: /var/local/media: wrong fs type, bad option, bad superblock on
/dev/sdb, missing codepage or helper program, or other error.

excerpt from dmesg:

[  352.642893] BTRFS info (device sdb): disk space caching is enabled
[  352.642897] BTRFS info (device sdb): has skinny extents
[  352.645562] BTRFS error (device sdb): devid 2 uuid
bf09cc8f-44d6-412e-bc42-214ff122584a is missing
[  352.645570] BTRFS error (device sdb): failed to read the system array: -2
[  352.646770] BTRFS error (device sdb): open_ctree failed

Is there anything I can do to attempt to recover this hardware issue?

This is a 2+ device Btrfs file system? And one of the devices, devid2,
is missing. So you need to figure out why. If the drive has in fact
failed, rather than just missing power/data connection, you can mount
degraded using the 'degraded' mount option. Just be advised that there
are potentially some consequences to operating under degraded mode,
depending on the specific configuration.

Thanks for the hints, Chris. Appreciated.

What sort of potential consequences are we talking about, if you could
elaborate?

Cheers,

-m