On 2020-07-11 03:37, Chris Murphy wrote:
Summary:
df claims this volume is full, which is how it actually behaves. Rsync
fails with an out of space message. But 'btrfs fi us' reports
seemingly misleading/incorrect information:
Free (estimated): 12.64GiB (min: 6.33GiB)
If Btrfs can't do single device raid0, and it seems it can't, then
this free space reporting seems wrong twice. (Both values.)
Details:
# uname -r
5.8.0-0.rc3.20200701git7c30b859a947.1.fc33.x86_64
# btrfs --version
btrfs-progs v5.7
# btrfs fi show
Label: 'fedora_localhost-live' uuid: 1fa3ab85-2dec-46f8-9a35-264c0f412dcc
Total devices 2 FS bytes used 885.83MiB
devid 1 size 730.00MiB used 709.00MiB path /dev/vda3
devid 2 size 13.30GiB used 709.00MiB path /dev/vdb1
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/vda3 15G 905M 60M 94% /mnt/sysroot
# btrfs fi us /mnt/sysroot
Overall:
Device size: 14.01GiB
Device allocated: 1.38GiB
Device unallocated: 12.63GiB
Device missing: 0.00B
Used: 901.58MiB
Free (estimated): 12.64GiB (min: 6.33GiB)
Data ratio: 1.00
Metadata ratio: 2.00
Global reserve: 3.25MiB (used: 0.00B)
Multiple profiles: no
Data,RAID0: Size:890.00MiB, Used:870.08MiB (97.76%)
/dev/vda3 445.00MiB
/dev/vdb1 445.00MiB
Metadata,RAID1: Size:256.00MiB, Used:15.73MiB (6.15%)
/dev/vda3 256.00MiB
/dev/vdb1 256.00MiB
System,RAID1: Size:8.00MiB, Used:16.00KiB (0.20%)
/dev/vda3 8.00MiB
/dev/vdb1 8.00MiB
Unallocated:
/dev/vda3 21.00MiB
/dev/vdb1 12.61GiB
#
The problem is no unallocated space on vda3, so there is not enough
space to allocate another RAID chunk.RAID0,RAID1 and higher requires
that block groups are allocated on minimum of two devices.
You could convert to DUP or SINGLE profile to free up space and then do
a full balance.
