I am testing btrfs on kvm guest, currently i have found: * Bug 894837 - Transient / Intermittent ENOSPC errors with BTRFS and F18 (btrfs gives no space left on device at full or near full filesystem and heavy io, for example deleting stuff to reclaim space.) -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel