Re: Data single *and* raid?

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

Hendrik Friedel wrote on 2015/08/06 20:57 +0200:
> Hello Hugo,
> hello Chris,
>
> thanks for your advice. Now I am here:
> btrfs balance start -dprofiles=single -mprofiles=raid1
> /mnt/__Complete_Disk/
> Done, had to relocate 0 out of 3939 chunks
>
>
> root@homeserver:/mnt/__Complete_Disk# btrfs fi show
> Label: none  uuid: a8af3832-48c7-4568-861f-e80380dd7e0b
>          Total devices 3 FS bytes used 3.78TiB
>          devid    1 size 2.73TiB used 2.72TiB path /dev/sde
>          devid    2 size 2.73TiB used 2.23TiB path /dev/sdc
>          devid    3 size 2.73TiB used 2.73TiB path /dev/sdd
>
> btrfs-progs v4.1.1
>
>
> So, that looks good.
>
> But then:
> root@homeserver:/mnt/__Complete_Disk# btrfs fi df /mnt/__Complete_Disk/
> Data, RAID5: total=3.83TiB, used=3.78TiB
> System, RAID5: total=32.00MiB, used=576.00KiB
> Metadata, RAID5: total=6.46GiB, used=4.84GiB
> GlobalReserve, single: total=512.00MiB, used=0.00B
GlobalReserve is not a chunk type, it just means a range of metadata 
reserved for overcommiting.
And it's always single.

Personally, I don't think it should be output in "fi df" command, as 
it's in a higher level than chunk.

At least for your case, nothing is needed to worry about.

Thanks,
Qu

>
> Is the RAID5 expected here?
> I did not yet run:
> btrfs balance start -dconvert=raid5,soft -mconvert=raid5,soft
> /mnt/new_storage/
>
> Regards,
> Hendrik
>
>
> On 01.08.2015 22:44, Chris Murphy wrote:
>> On Sat, Aug 1, 2015 at 2:32 PM, Hugo Mills <hugo@carfax.org.uk> wrote:
>>> On Sat, Aug 01, 2015 at 10:09:35PM +0200, Hendrik Friedel wrote:
>>>> Hello,
>>>>
>>>> I converted an array to raid5 by
>>>> btrfs device add /dev/sdd /mnt/new_storage
>>>> btrfs device add /dev/sdc /mnt/new_storage
>>>> btrfs balance start -dconvert=raid5 -mconvert=raid5 /mnt/new_storage/
>>>>
>>>> The Balance went through. But now:
>>>> Label: none  uuid: a8af3832-48c7-4568-861f-e80380dd7e0b
>>>>          Total devices 3 FS bytes used 5.28TiB
>>>>          devid    1 size 2.73TiB used 2.57TiB path /dev/sde
>>>>          devid    2 size 2.73TiB used 2.73TiB path /dev/sdc
>>>>          devid    3 size 2.73TiB used 2.73TiB path /dev/sdd
>>>> btrfs-progs v4.1.1
>>>>
>>>> Already the 2.57TiB is a bit surprising:
>>>> root@homeserver:/mnt# btrfs fi df /mnt/new_storage/
>>>> Data, single: total=2.55TiB, used=2.55TiB
>>>> Data, RAID5: total=2.73TiB, used=2.72TiB
>>>> System, RAID5: total=32.00MiB, used=736.00KiB
>>>> Metadata, RAID1: total=6.00GiB, used=5.33GiB
>>>> Metadata, RAID5: total=3.00GiB, used=2.99GiB
>>>
>>>     Looking at the btrfs fi show output, you've probably run out of
>>> space during the conversion, probably due to an uneven distribution of
>>> the original "single" chunks.
>>>
>>>     I think I would suggest balancing the single chunks, and trying the
>>> conversion (of the unconverted parts) again:
>>>
>>> # btrfs balance start -dprofiles=single -mprofile=raid1
>>> /mnt/new_storage/
>>> # btrfs balance start -dconvert=raid5,soft -mconvert=raid5,soft
>>> /mnt/new_storage/
>>>
>>
>> Yep I bet that's it also. btrfs fi usage might be better at exposing
>> this case.
>>
>>
>
>