unable to replace defect raid1 device

unable to replace defect raid1 device

[Michael Kofler]

on Ubuntu 10.10 alpha with btrfs 0.19 and a 2.6.35
(2.6.35-12-generic #17-Ubuntu SMP Mon Jul 26 18:48:06)

I created a btrfs raid 1 system:

# mkfs.btrfs -d raid1 -m raid1 /dev/sdb1 /dev/sdc1

Then I rebooted without disk 3 (/dev/sdc). I was able to mount the btrfs 
with mount -o degraded.

However, I was not able to remove the defect device.

# btrfs device delete /dev/sdc1
ERROR: error removing the device '/dev/sdc1'
# dmesg | tail
...
[  110.524145] btrfs: allowing degraded mounts
[  439.104487] btrfs: unable to go below two devices on raid1

I was able to add a new device (again /dev/sdc1, but on another disk), 
but apparently it was not used as a raid1 device:

# btrfs de add /dev/sdc1 /media/btrfs/
# btrfs fi sh
Label: none  uuid: dc691a5d-187e-4cb4-a94a-d12dabdffde4
	Total devices 3 FS bytes used 3.76GB
	devid    1 size 8.00GB used 5.35GB path /dev/sdb1
	devid    3 size 8.00GB used 0.00 path /dev/sdc1
	*** Some devices missing

Is there a way to replace a defect raid1 device as with mdadm?
Or is this not yet implemented in btrfs?

Best wishes,

	Michael Kofler

Re: unable to replace defect raid1 device

[C Anthony Risinger]

Try to add replacement, rebalance, then remove missing

C Anthony [mobile]

On Jul 31, 2010, at 2:04 PM, Michael Kofler <michael@kofler.info> wrote:

> on Ubuntu 10.10 alpha with btrfs 0.19 and a 2.6.35
> (2.6.35-12-generic #17-Ubuntu SMP Mon Jul 26 18:48:06)
>
> I created a btrfs raid 1 system:
>
> # mkfs.btrfs -d raid1 -m raid1 /dev/sdb1 /dev/sdc1
>
> Then I rebooted without disk 3 (/dev/sdc). I was able to mount the
> btrfs with mount -o degraded.
>
> However, I was not able to remove the defect device.
>
> # btrfs device delete /dev/sdc1
> ERROR: error removing the device '/dev/sdc1'
> # dmesg | tail
> ...
> [  110.524145] btrfs: allowing degraded mounts
> [  439.104487] btrfs: unable to go below two devices on raid1
>
> I was able to add a new device (again /dev/sdc1, but on another
> disk), but apparently it was not used as a raid1 device:
>
> # btrfs de add /dev/sdc1 /media/btrfs/
> # btrfs fi sh
> Label: none  uuid: dc691a5d-187e-4cb4-a94a-d12dabdffde4
>    Total devices 3 FS bytes used 3.76GB
>    devid    1 size 8.00GB used 5.35GB path /dev/sdb1
>    devid    3 size 8.00GB used 0.00 path /dev/sdc1
>    *** Some devices missing
>
> Is there a way to replace a defect raid1 device as with mdadm?
> Or is this not yet implemented in btrfs?
>
> Best wishes,
>
>    Michael Kofler
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