Btrfs

Btrfs (pronounced as "better F S", "butter F S", "b-tree F S", or simply by spelling it out) is a computer storage format that combines a based on the copy-on-write (COW) principle with a logical volume manager (not to be confused with Linux's LVM), developed together. It was founded by Chris Mason in 2007 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel. Btrfs is intended to address the lack of pooling, snapshots, checksums, and integral multi-device spanning in . Chris Mason, the principal Btrfs author, stated that its goal was "to let [Linux] scale for the storage that will be available. Scaling is not just about addressing the storage but also means being able to administer and to manage it with a clean interface that lets people see what's being used and makes it more reliable". The core data structure of Btrfsthe copy-on-write B-treewas originally proposed by IBM researcher Ohad Rodeh at a presentation at USENIX 2007. Chris Mason, an engineer working on ReiserFS for SUSE at the time, joined Oracle later that year and began work on a new file system based on these B-trees. In 2008, the principal developer of the ext3 and ext4 file systems, Theodore Ts'o, stated that although ext4 has improved features, it is not a major advance; it uses old technology and is a stop-gap. Ts'o said that Btrfs is the better direction because "it offers improvements in scalability, reliability, and ease of management". Btrfs also has "a number of the same design ideas that reiser3/4 had". Btrfs 1.0, with finalized on-disk format, was originally slated for a late-2008 release, and was finally accepted into the Linux kernel mainline in 2009. Several Linux distributions began offering Btrfs as an experimental choice of during installation. In July 2011, Btrfs automatic defragmentation and scrubbing features were merged into version 3.0 of the Linux kernel mainline. Besides Mason at Oracle, Miao Xie at Fujitsu contributed performance improvements.