How to make a redundant desktop system with daily snapshots? (Is btrfs ready for use?)

While nobody has officially blessed it, I'd personally guess that it's ready for production use.

Some reasons that are typically given for not using it in production: the on-disk format may not be stable, there is no btrfsck, there is no support available. So let's examine those:

• The on-disk format is now stable and the Btrfs developers have committed to maintaining compatibility, since 2009. That's 3 years.

• There is a filesystem checker now. Also, this checker is shipped in Linux distributions, you no longer need to build it from source yourself.

• Enterprise Btrfs support is now available from Oracle and SUSE (and has been since February).

That last one is what really says it for me. If Oracle – the company that maintains the software – is now willing to give you commercial support for it, then it's probably ready. Of course they have a strong interest in never saying that the open source version (which is, as far as I know, the same software, just no support contract) is actually ready for use, because they want you to buy the support and of course they don't want to be blamed if you go off by yourself and do something unsupported and blow up your disks, but I doubt they'd be willing to support it at all if they really thought it would lose data.