BTRFS is and will be for the time being in development. This is being shown in the BTRFS FAQ page:

Is btrfs stable?

• Short answer: Maybe.


• Long answer: Nobody is going to magically stick a label on the btrfs code and say "yes, this is now stable and bug-free". Different people have different concepts of stability: a home user who wants to keep their ripped CDs on it will have a different requirement for stability than a large financial institution running their trading system on it. If you are concerned about stability in commercial production use, you should test btrfs on a testbed system under production workloads to see if it will do what you want of it. In any case, you should join the mailing list (and hang out in IRC) and read through problem reports and follow them to their conclusion to give yourself a good idea of the types of issues that come up, and the degree to which they can be dealt with. Whatever you do, we recommend keeping good, tested, off-system (and off-site) backups.


• Pragmatic answer: (2012-12-19) Many of the developers and testers run btrfs as their primary filesystem for day-to-day usage, or with various forms of "real" data. With reliable hardware and up-to-date kernels, we see very few unrecoverable problems showing up. As always, keep backups, test them, and be prepared to use them.

This also applies to Ubuntu implementation of BTRFS.