Re: Can't replace a faulty disk of raid1

["Lluís Batlle i Rossell" <viric@viric.name>]

Another topposting detail:

I've run "btrfs scrub start /", and it finished properly. So it seems my data is
still there:
scrub status for 2ebf9e90-104c-47a4-adff-fada1ce3b682
        scrub started at Fri Oct 26 10:13:21 2012, running for 7719 seconds
        total bytes scrubbed: 434.54GB with 0 errors

If someone asks what can be "Data: total=25.32GB, used=22.48GB", it may come
from a "balance start -dconvert=single /" I had started *before* I unplugged the
faulty disk, but at some point cancelled it.

Thank you in advance,
Lluís.

On Fri, Oct 26, 2012 at 12:57:21PM +0200, Lluís Batlle i Rossell wrote:
> Hello,
> 
> I had a raid1 btrfs (540GB) on vanilla 3.6.3, a disk failed, and removed it at
> power off, plugged in a new one, partitioned it (to 110GB, by error), and added
> it to btrfs.
> 
> I tried to remove the missing device, and it said "Input/output error" after a
> while. Next attempts simply gave "Invalid argument".
> 
> I repartitioned, rebooted the system, and made the partition grow: "btrfs fi
> resize 3:max /"
> 
> # btrfs fi show
> Label: 'mainbtrfs'  uuid: 2ebf9e90-104c-47a4-adff-fada1ce3b682
>     Total devices 3 FS bytes used 445.06GB
>     devid    1 size 539.95GB used 539.95GB path /dev/sda5
>     devid    3 size 539.95GB used 96.90GB path /dev/sdb1   <= New disk
>     *** Some devices missing
> 
> The size appeared fine (I checked it at byte-amount level, to ensure I have not
> set 4K smaller for example). But attempting the 'btrfs device delete missing /'
> again gave the same outcome.
> 
> I tried "btrfs balance start /", and after a while, also ends with "Input/output
> error". In any of the cases above, I have an error message in dmesg. dmesg only
> shows usual 'relocating block...' and 'found 4 extents'.
> 
> I see that the /dev/sdb1, in any operation above I do, never goes beyond those 'used
> 96.90GB'. So, I'm stuck not being able to go back to raid1, with a degraded
> mount.
> 
> Some data:
> 
> # btrfs fi df /
> Data, RAID1: total=507.62GB, used=417.08GB
> Data: total=25.32GB, used=22.48GB
> System, RAID1: total=32.00MB, used=92.00KB
> System: total=4.00MB, used=0.00
> Metadata, RAID1: total=19.97GB, used=5.50GB
> 
> Mount log:
> [   10.939163] device label mainbtrfs devid 1 transid 194548 /dev/sda5
> [   10.939856] btrfs: allowing degraded mounts
> [   10.939939] btrfs: disk space caching is enabled
> [   10.940652] warning devid 2 missing
> [   10.987500] btrfs: bdev (null) errs: wr 6702, rd 2632, flush 312, corrupt 1970, gen 573
> [   10.987636] btrfs: bdev /dev/sda5 errs: wr 52, rd 13, flush 0, corrupt 2, gen 8
> [   14.391309] btrfs: unlinked 1 orphans
> [   22.319849] btrfs: use lzo compression
> [   22.319937] btrfs: disk space caching is enabled
> [   27.481405] udevd[1451]: starting version 173
> [   28.493786] device label mainbtrfs devid 3 transid 194549 /dev/sdb1
> [   28.930870] device fsid 30781650-3053-4273-b640-ec86a442c945 devid 1 transid 2272 /dev/sda3
> [   28.947632] device label mainbtrfs devid 1 transid 194549 /dev/sda5
> 
> 
> Any help?
> 
> Thank you,
> Lluís.