Re: Interpreting `btrfs filesystem show'

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

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On Mon, Oct 15, 2018 at 05:24:08PM +0300, Anton Shepelev wrote:
> Hello, all
> 
> While trying to resolve free space problems, and found that
> I cannot interpret the output of:
> 
> > btrfs filesystem show
> 
> Label: none  uuid: 8971ce5b-71d9-4e46-ab25-ca37485784c8
>         Total devices 1 FS bytes used 34.06GiB
>         devid    1 size 40.00GiB used 37.82GiB path /dev/sda2
> 
> How come the total used value is less than the value listed
> for the only device?

   "Used" on the device is the mount of space allocated. "Used" on the
FS is the total amount of actual data and metadata in that allocation.

   You will also need to look at the output of "btrfs fi df" to see
the breakdown of the 37.82 GiB into data, metadata and currently
unused.

   See https://btrfs.wiki.kernel.org/index.php/FAQ#Understanding_free_space.2C_using_the_original_tools for the details.

   Hugo.

-- 
Hugo Mills             | "Your problem is that you have a negative
hugo@... carfax.org.uk | personality."
http://carfax.org.uk/  | "No, I don't!"
PGP: E2AB1DE4          |                              Londo and Vir, Babylon 5

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