Re: Out of space error even though there's 100 GB unused?

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

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On Wed, Jul 06, 2016 at 11:55:42AM +0200, Stanislaw Kaminski wrote:
> Hi,
> I am fighting with this since at least Monday - see
> https://superuser.com/questions/1096658/btrfs-out-of-space-even-though-there-should-be-10-left
> 
> Here's the data:
> #   uname -a
> Linux archb3 4.6.3-2-ARCH #1 PREEMPT Wed Jun 29 07:15:33 MDT 2016
> armv5tel GNU/Linux
> 
> #   btrfs --version
> btrfs-progs v4.6
> 
> #   btrfs fi show
> Label: 'home'  uuid: 1c7e35e8-f013-4f65-9d19-eaa168ac088b
>         Total devices 1 FS bytes used 1.71TiB
>         devid    1 size 1.81TiB used 1.71TiB path /dev/sda4

   In this state, you should definitely not be seeing out of space
errors. This is, therefore, a bug you're seeing.

   I've not been following things as closely as I'd like of late, but
I think there was a bug recently involving the free space cache. It
might be worth unmounting the FS and mounting again with the
nospace_cache option, just to see if that helps.

   Hugo.

> #   btrfs fi df /home
> Data, single: total=1.71TiB, used=1.71TiB
> System, DUP: total=32.00MiB, used=224.00KiB
> Metadata, DUP: total=4.00GiB, used=2.07GiB
> GlobalReserve, single: total=512.00MiB, used=0.00B
> 
> # btrfs f usage -T  /home
> Overall:
>     Device size:                   1.81TiB
>     Device allocated:              1.71TiB
>     Device unallocated:           97.89GiB
>     Device missing:                  0.00B
>     Used:                          1.71TiB
>     Free (estimated):             98.22GiB      (min: 49.27GiB)
>     Data ratio:                       1.00
>     Metadata ratio:                   2.00
>     Global reserve:              512.00MiB      (used: 0.00B)
> 
>              Data    Metadata System
> Id Path      single  DUP      DUP       Unallocated
> -- --------- ------- -------- --------- -----------
>  1 /dev/sda4 1.71TiB  8.00GiB  64.00MiB    97.89GiB
> -- --------- ------- -------- --------- -----------
>    Total     1.71TiB  4.00GiB  32.00MiB    97.89GiB
>    Used      1.71TiB  2.07GiB 224.00KiB
> 
> # btrfs fi du -s /home
> Total Exclusive Set shared Filename
> 1.60TiB 1.60TiB 0.00B /home
> 
> # btrfs f resize 1:+1G /home/
> Resize '/home/' of '1:+1G'
> ERROR: unable to resize '/home/': no enough free space
> 
> This all is after closely following:
> https://btrfs.wiki.kernel.org/index.php/FAQ#Help.21_I_ran_out_of_disk_space.21
> http://marc.merlins.org/perso/btrfs/post_2014-05-04_Fixing-Btrfs-Filesystem-Full-Problems.html
> 
> So, already did full volume rebalance, defrag, rebooted multiple times
> - still, "Error: out of disk space".
> 
> To sum up:
> - my files sum to 1.6 TiB
> - disk usage is shown to be 1.71 TiB
> - volume size is 1.81 TiB
> - btrfs util shows I have ~98 GiB free space on the volume
> - I am getting "out of space" message
> 
> Bonus:
> - I removed 50 GB of data from the drive and I still get "out of
> space" message after writing ~1 GB.
> 
> Help would be very appreciated.
> 
> Cheers,
> Stan

-- 
Hugo Mills             | You can play with your friends' privates, but you
hugo@... carfax.org.uk | can't play with your friends' childrens' privates.
http://carfax.org.uk/  |
PGP: E2AB1DE4          |                                       C++ coding rule

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