Re: illegal snapshot, cannot be deleted

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

[-- Attachment #1: Type: text/plain, Size: 2648 bytes --]

On Fri, Nov 13, 2015 at 01:10:12PM -0500, Austin S Hemmelgarn wrote:
> On 2015-11-13 12:30, Vedran Vucic wrote:
> >Hello,
> >
> >Here are outputs of commands as you requested:
> >  btrfs fi df /
> >Data, single: total=8.00GiB, used=7.71GiB
> >System, DUP: total=32.00MiB, used=16.00KiB
> >Metadata, DUP: total=1.12GiB, used=377.25MiB
> >GlobalReserve, single: total=128.00MiB, used=0.00B
> >
> >btrfs fi show
> >Label: none  uuid: d6934db3-3ac9-49d0-83db-287be7b995a5
> >         Total devices 1 FS bytes used 8.08GiB
> >         devid    1 size 18.71GiB used 10.31GiB path /dev/sda6
> >
> >btrfs-progs v4.0+20150429
> >
> Hmm, that's odd, based on these numbers, you should be having no
> issue at all trying to run a balance. You might be hitting some
> other bug in the kernel, however, but I don't remember if there were
> any known bugs related to ENOSPC or balance in the version you're
> running.

   There's one specific bug that shows up with ENOSPC exactly like
this. It's in all versions of the kernel, there's no known solution,
and no guaranteed mitigation strategy, I'm afraid. Various things like
balancing, or adding, balancing, and removing a device again have been
tried. Sometimes they seem to help; sometimes they just make the
problem worse.

   We average maybe one report a week or so(*) with this particular
set of symptoms.

   Hugo.

(*) <waves hands vaguely>

>  You might see if trying to re-run the balance with
> '-dusage=40 -musage=40' works correctly (I've seen cases where the
> first run fails, but subsequent ones work because the first one made
> some progress despite failing).
> >On Fri, Nov 13, 2015 at 5:30 PM, Austin S Hemmelgarn
> ><ahferroin7@gmail.com> wrote:
> >>On 2015-11-13 11:12, Vedran Vucic wrote:
> >>>
> >>>Hello,
> >>>
> >>>I succeeded to delete illegal snapshot with command:
> >>>btrfs subvolume delete /.snapshots/741/snapshot
> >>>When I have done
> >>>btrfs balance / -dusage=0 -musage=0
> >>>increasing value up to 4o I did not have issues.
> >>>But on value 4- for-dusage= and -musage=
> >>>I got message that there is no space left on disk.
> >>>Do you have any advice how to manage that?
> >>
> >>
> >>Can you post the output of 'btrfs fi df' and 'btrfs fi show' again? Both
> >>should have changed after the balance, and I'd need to see what it looks
> >>like now to be able to give any reasonable advice.
> >>
> >>
> 
> 



-- 
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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]