Lester B
2013-Oct-27 20:09 UTC
Total fs size does not match with the actual size of the setup
The btrfs setup only have one device of size 7 GiB but when I run df, the total size shown is 15 GiB. Running btrfs --repair displays an error "cache and super generation don''t match, space cache will be invalidated." How can I correct the total fs size as shown in df? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hugo Mills
2013-Oct-27 20:17 UTC
Re: Total fs size does not match with the actual size of the setup
On Mon, Oct 28, 2013 at 04:09:18AM +0800, Lester B wrote:> The btrfs setup only have one device of size 7 GiB but > when I run df, the total size shown is 15 GiB. Running > btrfs --repairI''d recommend not running btrfs check --repair unless you really know what you''re doing, or you''ve checked with someone knowledgable and they say you should try it. On a non-broken filesystem (as here), it''s probably OK, though.> displays an error "cache and super > generation don''t match, space cache will be invalidated."This is harmless.> How can I correct the total fs size as shown in df?You can''t. It''s an artefact of the fact that you''ve got a RAID-1 (or RAID-10, or --mixed and DUP) filesystem, and that the standard kernel interface for df doesn''t allow us to report the correct figures -- see [1] (and the subsequent entry as well) for a more detailed description. Hugo. [1] https://btrfs.wiki.kernel.org/index.php/FAQ#Why_does_df_show_incorrect_free_space_for_my_RAID_volume.3F -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk == PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- Nothing right in my left brain. Nothing left in --- my right brain.
Lester B
2013-Oct-27 20:27 UTC
Re: Total fs size does not match with the actual size of the setup
2013/10/28 Hugo Mills <hugo@carfax.org.uk>:> On Mon, Oct 28, 2013 at 04:09:18AM +0800, Lester B wrote: >> The btrfs setup only have one device of size 7 GiB but >> when I run df, the total size shown is 15 GiB. Running >> btrfs --repair > > I''d recommend not running btrfs check --repair unless you really > know what you''re doing, or you''ve checked with someone knowledgable > and they say you should try it. On a non-broken filesystem (as here), > it''s probably OK, though. > >> displays an error "cache and super >> generation don''t match, space cache will be invalidated." > > This is harmless. > >> How can I correct the total fs size as shown in df? > > You can''t. It''s an artefact of the fact that you''ve got a RAID-1 > (or RAID-10, or --mixed and DUP) filesystem, and that the standard > kernel interface for df doesn''t allow us to report the correct figures > -- see [1] (and the subsequent entry as well) for a more detailed > description. > > Hugo. > > [1] https://btrfs.wiki.kernel.org/index.php/FAQ#Why_does_df_show_incorrect_free_space_for_my_RAID_volume.3F > > -- > === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ==> PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk > --- Nothing right in my left brain. Nothing left in --- > my right brain.But my setup is a simple one without any RAID levels or other things so at least df size column should show the actual size of my setup. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Brendan Hide
2013-Oct-27 21:34 UTC
Re: Total fs size does not match with the actual size of the setup
On 2013/10/27 10:27 PM, Lester B wrote:> 2013/10/28 Hugo Mills <hugo@carfax.org.uk>: >> On Mon, Oct 28, 2013 at 04:09:18AM +0800, Lester B wrote: >>> The btrfs setup only have one device of size 7 GiB but >>> when I run df, the total size shown is 15 GiB. Running >>> btrfs --repair >> I''d recommend not running btrfs check --repair unless you really >> know what you''re doing, or you''ve checked with someone knowledgable >> and they say you should try it. On a non-broken filesystem (as here), >> it''s probably OK, though. >> >>> displays an error "cache and super >>> generation don''t match, space cache will be invalidated." >> This is harmless. >> >>> How can I correct the total fs size as shown in df? >> You can''t. It''s an artefact of the fact that you''ve got a RAID-1 >> (or RAID-10, or --mixed and DUP) filesystem, and that the standard >> kernel interface for df doesn''t allow us to report the correct figures >> -- see [1] (and the subsequent entry as well) for a more detailed >> description. >> >> Hugo. >> >> [1] https://btrfs.wiki.kernel.org/index.php/FAQ#Why_does_df_show_incorrect_free_space_for_my_RAID_volume.3F >> >> -- >> === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ==>> PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk >> --- Nothing right in my left brain. Nothing left in --- >> my right brain. > > But my setup is a simple one without any RAID levels or other things so at least > df size column should show the actual size of my setup.Could you send us the output of the following?: btrfs fi df <mountpoint> (where <mountpoint> is the path where the btrfs is mounted.) -- __________ Brendan Hide http://swiftspirit.co.za/ http://www.webafrica.co.za/?AFF1E97 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Lester B
2013-Oct-27 21:49 UTC
Re: Total fs size does not match with the actual size of the setup
sudo btrfs fi df <mountpoint> Data: total=5.62GB, used=4.96GB System: total=32.00MB, used=4.00KB Metadata: total=512.00MB, used=288.70MB -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html