"Btrfs (B-tree file system, variously pronounced "Butter F S", "Butterfuss", "Better F S", or "B-tree F S") is a GPL-licensed copy-on-write file system for Linux. Development began at Oracle Corporation in 2007. It is still in heavy development and marked as unstable"
But then there´s another view:
LinuxCon Japan 2012 | Presentations
"On The Way to a Healthy Btrfs Towards Enterprise"
by Liu Bo, Fujitsu
Let me quote:
"Btrfs has been on full development for about 5 years and it does make lots of progress on both features and performance, but why does everybody keep tagging it with ""experimental""? And why do people
still think of it as a vulnerable one for production use? As a goal of production use, we have been strengthening several features, making improvements on performance and keeping fixing bugs to make btrfs
stable, for instance, ""snapshot aware defrag"", ""extent buffer cache"", ""rbtree lock contention"", etc. This talk will cover the above"
From its web "Liu Bo has been working on Linux kernel development since late 2010 as a Fujitsu engineer. He has been working on filesystem field and he's now focusing on btrfs development".
RHEL 7 to get Btrfs support
"RHEL 7 will support ext4, XFS, and Btrfs (boot and data)"
Then you have SuSE:
"With SUSE Linux Enterprise 11 SP2, the btrfs file system joins ext3, reiserfs, xfs and ocfs2 as *commercially supported file systems*. Each file system offers disctinct advantages. While the installation
default is ext3, we recommend xfs when maximizing data performance is desired, and *btrfs as a root file system when snapshotting and rollback capabilities are required. Btrfs is supported as a root file
system (i.e. the file system for the operating system) across all architectures of SUSE Linux Enterprise 11 SP2*. "
"OL6.3 that boots up uek (2.6.39-200.24.1) as install kernel and uses btrfs as the default filesystem for installation. So latest and greatest direct access to btrfs, a modern well-tested, current kernel,
freely available. "
So, again, why does people insist in calling Btrfs "experimental" and "unstable"?. Do you think SUSE and Oracle both ship an unstable FS as a comercially supported feature??.
Sheesh, I´ve lost data with IBM´s "supposedly ´GA´" version of JFS for OS/2 once...
Back to Btrfs... it´s in the mainline Linux Kernel since February so with the adoption by RHEL 7, it´ll become mainstream sooner rather than later...
Here is a good video to get you interested on Btrfs and why it matters...
Just my $0.02...