Hi Hugo,
Thanks for your answer.
Unfortunately, I had also tried
sudo mount -o degraded /dev/sdc1 /samples
mount: wrong fs type, bad option, bad superblock on /dev/sdc1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
and dmesg says:
[ 1177.695773] btrfs: open_ctree failed
[ 1247.448766] device fsid 545e95c6-d347-4a8c-8a49-38b9f9cb9add devid
2 transid 31105 /dev/sdc1
[ 1247.449700] device fsid 545e95c6-d347-4a8c-8a49-38b9f9cb9add devid
1 transid 31105 /dev/sdc6
[ 1247.458794] device fsid 545e95c6-d347-4a8c-8a49-38b9f9cb9add devid
2 transid 31105 /dev/sdc1
[ 1247.459601] device fsid 545e95c6-d347-4a8c-8a49-38b9f9cb9add devid
1 transid 31105 /dev/sdc6
[ 4013.363254] device fsid 545e95c6-d347-4a8c-8a49-38b9f9cb9add devid
2 transid 31105 /dev/sdc1
[ 4013.408280] btrfs: allowing degraded mounts
[ 4013.555764] btrfs: bdev (null) errs: wr 0, rd 14, flush 0, corrupt 0, gen 0
[ 4015.600424] Btrfs: too many missing devices, writeable mount is not allowed
[ 4015.630841] btrfs: open_ctree failed
Yes, I know, I'll probably be losing a lot of data, but it's not "too
much" my concern because I had a backup (sooo happy about that :D). If
I can manage to recover a little more on the btrfs volume it's bonus,
but in the event I do not, I'll be using my backup.
So, how do I fix my volume? I guess there would be a solution apart
from scratching/deleting everything and starting again...
Regards,
Axelle
On Fri, Feb 14, 2014 at 11:58 AM, Hugo Mills <h...@carfax.org.uk> wrote:
> On Fri, Feb 14, 2014 at 11:35:56AM +0100, Axelle wrote:
>> Hi,
>> I've just encountered a hard disk crash in one of my btrfs pools.
>>
>> sudo btrfs filesystem show
>> failed to open /dev/sr0: No medium found
>> Label: none uuid: 545e95c6-d347-4a8c-8a49-38b9f9cb9add
>> Total devices 3 FS bytes used 112.70GB
>> devid 1 size 100.61GB used 89.26GB path /dev/sdc6
>> devid 2 size 93.13GB used 84.00GB path /dev/sdc1
>> *** Some devices missing
>>
>> The device which is missing is /dev/sdb. I have replaced it with a new
>> hard disk. How do I add it back to the volume and fix the device
>> missing?
>> The pool is expected to mount to /samples (it is not mounted yet).
>>
>> I tried this - which fails:
>> sudo btrfs device add /dev/sdb /samples
>> ERROR: error adding the device '/dev/sdb' - Inappropriate ioctl for device
>>
>> Why isn't this working?
>
> Because it's not mounted. :)
>
>> I also tried this:
>> sudo mount -o recovery /dev/sdc1 /samples
>> mount: wrong fs type, bad option, bad superblock on /dev/sdc1,
>> missing codepage or helper program, or other error
>> In some cases useful info is found in syslog - try
>> dmesg | tail or so
>> same with /dev/sdc6
>
> Close, but what you want here is:
>
> mount -o degraded /dev/sdc1 /samples
>
> not "recovery". That will tell the FS that there's a missing disk, and
> it should mount without complaining. If your data is not RAID-1 or
> RAID-10, then you will almost certainly have lost some data.
>
> At that point, since you've removed the dead disk, you can do:
>
> btrfs device delete missing /samples
>
> which forcibly removes the record of the missing device.
>
> Then you can add the new device:
>
> btrfs device add /dev/sdb /samples
>
> And finally balance to repair the RAID:
>
> btrfs balance start /samples
>
> It's worth noting that even if you have RAID-1 data and metadata,
> losing /dev/sdc in your current configuration is likely to cause
> severe data loss -- probably making the whole FS unrecoverable. This
> is because the FS sees /dev/sdc1 and /dev/sdc6 as independent devices,
> and will happily put both copies of a piece of RAID-1 data (or
> metadata) on /dev/sdc -- one on each of sdc1 and sdc6. I therefore
> wouldn't recommend running like that for very long.
>
> Hugo.
>
> --
> === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
> PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
> --- All hope abandon, Ye who press Enter here. ---
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