Re: device delete, error removing device [SOLVED]

[Goffredo Baroncelli <kreijack@gmail.com>]

On 2012-10-24 00:29, Chris Murphy wrote:
> 
> On Oct 23, 2012, at 4:16 PM, Goffredo Baroncelli <kreijack@inwind.it>
> wrote:

> 
> I think it needs to be bigger. I was at a bit over 8GB file size for
> a 9GB file system (3x 3GB drives). There was about 300MB of free
> space left according to df -h, which was for the whole volume, i.e.
> maybe around 100MB free space per device, and hence possibly not
> enough room to budge unless I added yet another drive. Then it was
> able to back out.

I was able to reproduce it:

- I filled the filesystem until I got "No space left on device".
- Then I added a new device -> success
- I balanced -> success

The status is:
ghigo@emulato:~$ sudo /mnt/home-ghigo/btrfs/btrfs-progs/btrfs fi show
Label: 'test2'  uuid: 11d0f1a8-2770-4ff2-8df5-f772f1056edc
	Total devices 4 FS bytes used 8.29GB
	devid    4 size 12.00GB used 3.35GB path /dev/vdf
	devid    3 size 3.00GB used 2.53GB path /dev/vdd
	devid    2 size 3.00GB used 2.56GB path /dev/vdc
	devid    1 size 3.00GB used 2.55GB path /dev/vdb


Note the used space.

Then I removed /dev/vdb but I got

$ sudo /mnt/home-ghigo/btrfs/btrfs-progs/btrfs dev del /dev/vdb /mnt/btrfs1/
ERROR: error removing the device '/dev/vdb' - No space left on device


The interesting things is:

ghigo@emulato:~$ sudo /mnt/home-ghigo/btrfs/btrfs-progs/btrfs fi show
Label: 'test2'  uuid: 11d0f1a8-2770-4ff2-8df5-f772f1056edc
	Total devices 4 FS bytes used 7.63GB
	devid    4 size 12.00GB used 3.48GB path /dev/vdf
	devid    3 size 3.00GB used 3.00GB path /dev/vdd
	devid    2 size 3.00GB used 3.00GB path /dev/vdc
	devid    1 size 3.00GB used 2.55GB path /dev/vdb

So it seems that I spread all the data to the other disk, filling up the
smaller ones. So it stuck to "No space left on device".

Now I rebalanced with -dconvert=single, as suggested by Hugo, then I was
able to remove the disk:

Label: 'test2'  uuid: 11d0f1a8-2770-4ff2-8df5-f772f1056edc
	Total devices 3 FS bytes used 7.63GB
	devid    4 size 12.00GB used 9.48GB path /dev/vdf
	devid    3 size 3.00GB used 492.94MB path /dev/vdd
	devid    2 size 3.00GB used 64.00MB path /dev/vdc



GB
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