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
#
--
Chris Murphy
