From the draft of the new storage administration guide:
Btrfs is still being actively evaluated for stability during the Red Hat Enterprise Linux 7.0 beta. The following target use cases will only be fully supported if it passes our tests:
* The system partition only use case. This will allow btrfs only to get used for system installation, not only for a user's data. Currently it is unclear whether this will be restricted to this single disk or not.
* Use btrfs for desktop and laptop users including their data partitions.
* Use btrfs as the base file system under scale out "big data" file systems, such as gluster and Ceph.
Nice. http://en.wikipedia.org/wiki/Btrfs#Features