On CentOS7 I get "No space left on device errors" just now..
[root@m-admin03 ~]# btrfs scrub start /
WARNING: failed to write the progress status file: No space left on device. Status recording disabled
scrub started on /, fsid 25f5d19c-a4d3-4f28-9abb-699362765879 (pid=2833)
[root@m-admin03 ~]# btrfs scrub status /
scrub status for 25f5d19c-a4d3-4f28-9abb-699362765879
no stats available
total bytes scrubbed: 0.00 with 0 errors
[root@m-admin03 ~]# btrfs filesystem df /
Data, single: total=5.97GiB, used=4.45GiB
System, DUP: total=8.00MiB, used=16.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, DUP: total=341.38MiB, used=242.31MiB
Metadata, single: total=8.00MiB, used=0.00
GlobalReserve, single: total=96.00MiB, used=0.00
Sorry, I don't understand this..
In general, after a few weeks back in "Linuxland" (after more than 4 years FreeBSD/ZFS/jails).. Linux feels just sticky. FreeBSD is well-designed, secure and reliable compared to this.
Seen from FreeBSD, Linux is what Windows is to Linux: Just more "main stream" so everybody is scared of using "the exotic OS".
So I am quite ineffective at the moment, driving with the handbrake on.
As for the licensing: I could not be more bored. ZFS has a life outside Oracle.
If you need a storage appliance, use FreeNAS, I think. It beats Linux-based stuff by a mile.
Regards
Peter