Btrfs (pronounced ‘Butter F S’) is an advanced filesystem for Linux which can work across multiple hard disks and supports different fault tolerance models like RAID 0, RAID 1 and RAID 10. Btrfs has been in development since 2008 and it is what is known as a “copy on write” filesystem which means that when the data changes in a block, then the block will be copied a new block written to the disk with the changes incorporated. This means that blocks are never modified but rather new blocks are created and the old blocks are later reused. This has advantages for performance especially when ensuring consistency and integrity (even after a power interruption).

Full article here:
How to Use Btrfs On Newly Installed Disks (Make Tech Easier)

Related articles from ZDNet:
Btrfs hands on: My first experiments with a new Linux file system
Btrfs hands on: An extremely cool file system
Btrfs hands on: Exploring RAID and redundancy
Btrfs: Exploring its powerful filesystem subvolumes and snapshots
Btrfs hands-on: Exploring the error recovery features of the new Linux file system