Re: Unmountable btrfs filesystems

[Mark Nelson <mark.nelson@inktank.com>]

On 6/16/12 1:46 PM, Wido den Hollander wrote:
> Hi,
>
> On my dev cluster (10 nodes, 40 OSD's) I'm still trying to run Ceph on
> btrfs, but over the last couple of months I've lost multiple OSD's due
> to btrfs.
>
> On my nodes I've set kernel.panic=60 so that whenever a kernel panic
> occurs I get the node back within two minutes.
>
> Now, over the last time I've seen multiple nodes reboot (didn't see the
> strace), but afterwards the btrfs filesystems on that node were
> unmountable.
>
> "btrfs: open_ctree failed"
>
> I tried various kernels, the most recent 3.3.0 from kernel.ubuntu.com,
> but I'm still seeing this.
>
> Is anyone seeing the same or did everybody migrate away to ext4 or XFS?
>
> I still prefer btrfs due to the snapshotting, but loosing all these
> OSD's all the time is getting kind of frustrating.
>
> Any thoughts or comments?
>
> Wido
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Hi Wido,

btrfsck might tell you what's wrong.  Sounds like there is a 
btrfs-restore command in the dangerdonteveruse branch you could try. 
Beyond that, I guess it just really comes down to tradeoffs.

Good luck! ;)

Mark