I have to say that we have the production server running for 9 days over a BTRFS filesystem with no problem at all.
I had tested previously in test server.
And I have move the forum from place to a subvolume, added and removed disks and space from the filesystem, with no problem.
I will report after more time using it.
I am quite new to BTRFS and do not know it deeply, but it is not as difficult and it works as expected.