Re: No space left on device (again)

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

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On Tue, Feb 25, 2014 at 01:05:51PM -0500, Jim Salter wrote:
> 370GB of 410GB used isn't really "fine", it's over 90% usage.
> 
> That said, I'd be interested to know why btrfs fi show /dev/sda3
> shows 412.54G used, but btrfs fi df /home shows 379G used...

   This is an FAQ...

   btrfs fi show tells you how much is allocated out of the available
pool on each disk. btrfs fi df then shows how much of that allocated
space (in each category) is used.

   The problem here is also in the FAQ: the metadata is close to full
-- typically something like 500-750 MiB of headroom is needed in
metadata. The FS can't allocate more metadata because it's allocated
everything already (total=used in btrfs fi show), so the solution is
to do a filtered balance:

btrfs balance start -dusage=5 /mountpoint

   Hugo.

> 
> On 02/25/2014 11:49 AM, Marcus Sundman wrote:
> >Hi
> >
> >I get "No space left on device" and it is unclear why:
> >
> >># df -h|grep sda3
> >>/dev/sda3       413G  368G   45G  90% /home
> >># btrfs filesystem show /dev/sda3
> >>Label: 'home'  uuid: 46279061-51f4-40c2-afd0-61d6faab7f60
> >>    Total devices 1 FS bytes used 371.11GB
> >>    devid    1 size 412.54GB used 412.54GB path /dev/sda3
> >>
> >>Btrfs v0.20-rc1
> >># btrfs filesystem df /home
> >>Data: total=410.52GB, used=369.61GB
> >>System: total=4.00MB, used=64.00KB
> >>Metadata: total=2.01GB, used=1.50GB
> >>#
> >
> >So, 'data' and 'metadata' seem to be fine(?), but 'system' is a
> >bit low. Is that it? If so, can I do something about it? Or should
> >I look somewhere else?
> >
> >I really wish I could get a warning before running out of disk
> >space, instead of everything breaking suddenly when there seems to
> >be lots and lots of space left.
> >
> >- Marcus
> >

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

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