Re: btrfs balance on single device

[Hugo Mills <hugo@carfax.org.uk>]

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On Sun, Dec 15, 2013 at 08:20:19PM +0000, Leonidas Spyropoulos wrote:
> Hey all,
> 
> Just did a btrfs balance on a single device. Before the balance
> operation here is the df result:
> 
> inglor@tiamat ~$ btrfs fi df /home
> Data: total=19.19GB, used=9.34GB
> System, DUP: total=32.00MB, used=4.00KB
> Metadata, DUP: total=896.00MB, used=227.98MB
> 
> Then I issues a balance operation relocating the chunks across a single device:
> inglor@tiamat ~$ sudo btrfs fi balance /home
> [sudo] password for inglor:
> Done, had to relocate 28 out of 28 chunks
> 
> After I did another df:
> inglor@tiamat ~$ btrfs fi df /home
> Data: total=10.00GB, used=9.34GB
> System, DUP: total=32.00MB, used=4.00KB
> Metadata, DUP: total=384.00MB, used=226.80MB
> 
> Anyone can explain me the Data row of the above output ? It used to be
> 19.19GB and now it's 10.00GB. It's like the partition shrunk!? The
> balance operation finished without issues.

   It freed up some of the unused data chunks, returning them to the
unallocated space on the device.

> Here's some other information:
> 
> inglor@tiamat ~$ sudo btrfs filesystem show
> Label: 'home'  uuid: 458c70e2-7037-4c4d-bba2-3d5288f04510
>     Total devices 1 FS bytes used 9.56GB
>     devid    1 size 21.00GB used 10.81GB path /dev/sda3

   You can see that the filesystem is still the same size as before --
it's just that less of it is allocated.

   There's nothing to worry about here -- it's all working as expected.

   Hugo.

> Label: none  uuid: 699d671b-7064-441d-95ec-c616049fe287
>     Total devices 1 FS bytes used 13.94GB
>     devid    1 size 20.00GB used 20.00GB path /dev/sda2
> 
> Btrfs v0.20-rc1-358-g194aa4a-dirty
> inglor@tiamat ~$ df
> Filesystem     1K-blocks      Used Available Use% Mounted on
> /dev/sda2       20971520  15362816   3960288  80% /
> /dev/sda3       22020096  10256168  11375416  48% /home
> 
> Thanks,
> Leonidas
> 
> 

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
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