Btrfs is a new copy on write filesystem for Linux aimed at implementing advanced features while focusing on fault tolerance, repair and easy administration. Initially developed by Oracle, Btrfs is licensed under the GPL and open for contribution from anyone.
Linux has a wealth of filesystems to choose from, but we are facing a number of challenges with scaling to the large storage subsystems that are becoming common in today's data centers. Filesystems need to scale in their ability to address and manage large storage, and also in their ability to detect, repair and tolerate errors in the data stored on disk.
Btrfs is under heavy development, but every effort is being made to keep the filesystem stable and fast. As of 2.6.31, we only plan to make forward compatible disk format changes, and many users have been experimenting with Btrfs on their systems with good results. Please email the Btrfs mailing list if you have any problems or questions while using Btrfs.
The main Btrfs features include:
* 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)
* Integrated multiple device support, with several raid algorithms
* Online filesystem check
* Very fast offline filesystem check
* Efficient incremental backup and FS mirroring
* Online filesystem defragmentation
With current daily builds of Maverick, you should be able to perform installations with a btrfs root filesystem. This is still NOT RECOMMENDED FOR PRODUCTION USE and MAY EAT YOUR DATA, but we're making the option available by way of manual partitioning only so that we can experiment with btrfs more easily, contribute fixes to various tools as needed (as we've already done with grub2 in order to at least get this minimal level of support in place), and the like, and hopefully to encourage some more people to get involved in its development.
You cannot yet use btrfs for /boot (although we're working on this), so you'll need to create an ext3 or similar /boot filesystem. I assume anyone able to use an experimental filesystem can cope with doing that in the installer's manual partitioner.
Please file bugs as you encounter them! I expect that ext4 will remain the default filesystem for Maverick, but btrfs is doing a lot of things that are interesting for us down the line, so the sooner we can help to
iron out problems with it the better.
Source from here