Hi,
I have a banana pi with a btrfs filesystem of 5 GB in size, which
frequently runs out of space (lots of snapshots). This is currently
again the case:
[27/524]mh@banana:~$ sudo btrfs balance start /
ERROR: error during balancing '/' - No space left on device
There may be more info in syslog - try dmesg | tail
[28/525]mh@banana:~$ sudo btrfs balance start / -dlimit=3
[sudo] password for mh on banana:
ERROR: error during balancing '/' - No space left on device
There may be more info in syslog - try dmesg | tail
[29/526]mh@banana:~$ sudo btrfs balance start / -dlimit=3
ERROR: error during balancing '/' - No space left on device
There may be more info in syslog - try dmesg | tail
[30/526]mh@banana:~$ sudo btrfs balance start / -dusage=0
Done, had to relocate 0 out of 8 chunks
[31/527]mh@banana:~$ sudo btrfs balance start / -dlimit=3
ERROR: error during balancing '/' - No space left on device
There may be more info in syslog - try dmesg | tail
[32/528]mh@banana:~$ sudo btrfs fi show /
Label: none uuid: ada6b7f5-98d6-4fee-a3a3-b73bd152ff6c
Total devices 1 FS bytes used 3.37GiB
devid 1 size 6.89GiB used 4.22GiB path /dev/mapper/banana-root
btrfs-progs v4.3
[33/529]mh@banana:~$ sudo btrfs fi df /
Data, single: total=3.41GiB, used=3.25GiB
System, DUP: total=32.00MiB, used=16.00KiB
Metadata, DUP: total=384.00MiB, used=121.75MiB
GlobalReserve, single: total=48.00MiB, used=0.00B
[34/530]mh@banana:~$ uname -a
Linux banana 4.3.0-zgbpi-armmp-lpae+ #2 SMP Sat Nov 7 13:07:34 UTC 2015 armv7l GNU/Linux
[36/532]mh@banana:~$ df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/banana-root 6.9G 3.6G 2.9G 56% /
[37/533]mh@banana:~$
The first kernel that was ever booted on the device was 4.1, I am
therefore reasonably sure that the filesystem was also created with a
recent kernel. Is there any possibility to find out about the kernel
version that a filesystem was created with?
However, the FAQ
https://btrfs.wiki.kernel.org/index.php/FAQ#Help.21_Btrfs_claims_I.27m_out_of_space.2C_but_it_looks_like_I_should_have_lots_left.21
suggests that for small filesystems (<16 GB), the best solution would
be to upgrade to at least 2.6.37 and recreate the filesystem. 2.6.37
is ancient, from 2011, so I am pretty sure that the filesystem _was_
created at least with a kernel more recent than that.
My normal way to recover from this situation is to btrfs add a new
device, btrfs balance, btrfs --convert=single --force balance, btfs
device remove, btr balance start -mconvert=dup --force and finally
balance start again.
Is there any solution to solve this more elegantly?
Greetings
Marc
--
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Marc Haber | "I don't trust Computers. They | Mailadresse im Header
Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402
Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421
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