The announcement was featured at kerneltrap which also shows the most important features and discussions around Btrfs. There you also find the main features which are currently implemented (marked with a +) or which are supposed to be implemented in the future (marked with a -).
- + Extent based file storage (2^64 max file size)
- + Space efficient packing of small files
- + Space efficient indexed directories
- + Dynamic inode allocation
- + Writable snapshots
- + Subvolumes (separate internal filesystem roots)
- – Object level mirroring and striping
- + Checksums on data and metadata (multiple algorithms available)
- – Strong integration with device mapper for multiple device support
- – Online filesystem check
- +Very fast offline filesystem check
- – Efficient incremental backup and FS mirroring
Obviously, this reminds many people of ZFS – especially the snapshots are quite interesting, I think (think of backup solutions and versioned file systems here). But the file system is still in Alpha and in deep development. It has yet to show if it will be abpe to implement all planned features and if it will be able to become a new standard on Linux.
However, what I found most interesting was the fact that this new file system was developed at Oracle. Although Oracle attacked Red Hat with their unbreakable Linux the most kernel work is done by Red Hat in these days. The only bigger Oracle contribution I’m currently aware of is the Oracle Cluster File System 2, which is more interesting for larger deployments.
I wonder how many resources Oracle will put behind this development – and if their are other aims than providing a good file system. I’m still asking myself what their long term related to Red Hat is…
Anyway, if Btrfs would become stable, fast and usable quickly it could become the new standard for Linux file systems easily. At the moment everyone is looking at ZFS, but there are several problems why it is unlikely that it becomes part of Linux anytime soon. Btw., Dave Jones had a good point about the ZFS discussions: it is not all about the Licence. File systems in Linux are somewhat difficult and there are experienced reviewers missing to deal and properly integrate new file systems into the kernel.
However, since Oracle already brought another file system into the kernel and has lots of experiences in that field I hope that Btrfs matures well and becomes part of the mainline kernel soon. Just imagine the possibilities of a versioned file system in Linux within, say, 12 months. Ha, I like that.