A filesystem functions below the operating system, ensuring that abstract data is converted into physical address attributes such as tracks and sectors. Some filesystems go beyond this basic functionality. One powerful and popular filesystem for Linux is Btrfs. The Btrfs filesystem [1], which is affectionately pronounced "ButterFS," is sometimes called the next generation filesystem. Btrfs is a copy-on-write filesystem [2] originally developed by Oracle Corporation and masterminded by Chris Mason. In some ways, Btrfs is best understood as an implementation of the Solaris 10 transactional filesystem ZFS [3] for the Linux platform. Oracle acquired ZFS in 2010 when it acquired Sun Microsystems. Btrfs is free software under the GPL and was adopted into Linux kernel 2.6.29 early in 2009.

Btrfs was declared suitable for production use in April 2013. Btrfs developer Chris Mason moved from SUSE, where he worked on ReiserFS, to Oracle, and he has worked at Facebook for several years, where Btrfs is widely used in the back end. Btrfs is now no longer limited to Linux; the WinBtrfs [4] project offers what are still experimental drivers for Windows. In the Linux world, Oracle started using Btrfs in its Unbreakable Linux release, version 2, four years ago, and SUSE in SUSE Linux Enterprise Server 12 (SLES 12) and openSUSE 13.2 (Figure 1). OpeSUSE Leap uses Btrfs as the default for the root partition; most other distributions include Btrfs in their archives and offer it as an alternative in the installer. Fedora plans to make Btrfs the default with Fedora 24.

Figure 1: Btrfs as the default subvolume when installing openSUSE.

[...]