Btrfs

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Btrfs filesystem **DRAFT**

Summary

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.

For more detailed information can be found at the Btrfs homepage.

Purpose

The purpose of this page is not to duplicate information that can be found on other sites both internal and external but to consolidate and organize information and to make it Fedora specific where appropriate.

Btrfs support in Fedora

  • Btrfs has been available for testing as early as Fedora 11 but required a special boot parameter to be passed to Anaconda during installation.
  • In Fedora 15 it is available without a special boot parameter.
  • As of Fedora 16 it is slated to be the default filesystem.

Installing

Filesystem support is built into the kernel but you'll probably want to install the userspace programs:

yum install btrfs-progs

Conversions from Ext3/Ext4 volumes to Btrfs (and back!)

Important.png
Although Btrfs does not need LVM, if you already are using it then converting your volume does not remove LVM.
  • It is possible to convert back to Ext3/Ext4 as the metadata is stored as a subvolume. Once you delete the subvolume the conversion is permanent.
  • Some generic instructions can be found here.
  • Some untested (by me) instructions on fedoraforum.org are here.

Frequently Asked Question(s)

  • Why use (or not use) Btrfs?
    • The subvolume capability negates the need for LVM.
    • Filesystem based RAID 0/1/10.
    • Online resizing and addition/removal of disks.
    • Btrfs currently has limited fsck capability so make sure you backup your data!