I have six 8TB drives on a BTRFS RAID10 that I installed yesterday on Rockstor (centos 7). df reports the size correctly but space available is 5.7 TiB short of what I expected... what gives?
A metadata rebalance had almost no effect.
[root@big ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sdf 22T 3.3T 13T 22% /mnt2/main [root@big ~]# btrfs fi show /dev/sdf Label: 'main' uuid: 738d116b-ce5d-46cb-8c40-abb4a03b2071 Total devices 6 FS bytes used 3.30TiB devid 1 size 7.28TiB used 1.10TiB path /dev/sdf devid 2 size 7.28TiB used 1.10TiB path /dev/sdc devid 3 size 7.28TiB used 1.10TiB path /dev/sdb devid 4 size 7.28TiB used 1.10TiB path /dev/sdh devid 5 size 7.28TiB used 1.10TiB path /dev/sdd devid 6 size 7.28TiB used 1.10TiB path /dev/sdg [root@big ~]# btrfs fi df /mnt2/big Data, RAID10: total=3.30TiB, used=3.30TiB System, RAID10: total=7.88MiB, used=320.00KiB Metadata, RAID10: total=6.09GiB, used=3.63GiB GlobalReserve, single: total=512.00MiB, used=0.00B According to df -h, if I've only used 3.3TiB out of 22TiB, I should have ~18.7TiB Available, but it's reporting to the entire system that I have 13TiB available... 5.7TiB are missing in action
UPDATE: As i've been using it more, it seems to have grown by 2.2TiB. here is my latest df
Filesystem Size Used Avail Use% Mounted on /dev/sdf 22T 6.5T 12T 37% /mnt2/big 