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== Benchmarking ==
 
== Benchmarking ==
  
* '''2012-05 [http://www.phoronix.com/scan.php?page=article&item=linux_34_fs&num=1 XFS, Btrfs, EXT4 Battle It Out On Linux 3.4]'''
+
* '''2012-10''' [http://www.ilsistemista.net/index.php/linux-a-unix/36-btrfs-mount-options-and-virtual-machines-an-in-depth-look.html BTRFS, mount options and virtual machines: an in-depth look] (Ilsistemista.net)
* '''2012-05 [http://cd34.com/blog/scalability/ext4-xfs-and-btrfs-benchmark-redux/ Ext4, XFS and Btrfs benchmark redux]'''
+
* '''2012-06''' [http://www.ilsistemista.net/index.php/linux-a-unix/34-btrfs-ext3-ext4-xfs-and-kvm-virtual-machine-a-host-side-filesystem-comparison.html BTRFS EXT3 EXT4 XFS and KVM virtual machine: a host-side filesystem comparison] (Ilsistemista.net)
* '''2012-03 [http://www.phoronix.com/scan.php?page=article&item=linux_btrfs_options&num=1 Testing Out The Btrfs Mount Options On Linux 3.2]'''
+
* '''2012-06''' [http://www.ilsistemista.net/index.php/linux-a-unix/33-btrfs-vs-ext3-vs-ext4-vs-xfs-performance-on-fedora-17.html BTRFS vs EXT3 vs EXT4 vs XFS performance on Fedora 17] (Ilsistemista.net)
* '''2012-03 [http://www.phoronix.com/scan.php?page=article&item=ubuntu_1204_fs&num=1 Ubuntu 12.04 LTS - Benchmarking All The Linux File-Systems]'''
+
* '''2012-05''' [http://www.phoronix.com/scan.php?page=article&item=linux_34_fs&num=1 XFS, Btrfs, EXT4 Battle It Out On Linux 3.4] (Phoronix.com)
* '''2011-12 [http://btrfs.boxacle.net Btrfs Performance Analysis]'''
+
* '''2012-05''' [http://cd34.com/blog/scalability/ext4-xfs-and-btrfs-benchmark-redux/ Ext4, XFS and Btrfs benchmark redux]
* '''2011-11 [http://www.phoronix.com/vr.php?view=16773 Testing The "Pretty Beefy" Btrfs Changes In Linux 3.2]'''
+
* '''2012-03''' [http://www.phoronix.com/scan.php?page=article&item=linux_btrfs_options&num=1 Testing Out The Btrfs Mount Options On Linux 3.2] (Phoronix.com)
* '''2011-09 [http://www.phoronix.com/scan.php?page=article&item=btrfs_linux31_ssd&num=1 Testing EXT4 & Btrfs On A Serial ATA 3.0 SSD]'''
+
* '''2012-03''' [http://www.phoronix.com/scan.php?page=article&item=ubuntu_1204_fs&num=1 Ubuntu 12.04 LTS - Benchmarking All The Linux File-Systems] (Phoronix.com)
* '''2011-05 [http://www.phoronix.com/scan.php?page=article&item=linux_2639_fs&num=1 Linux 2.6.39: XFS Speeds-Up, EXT4 & Btrfs Unchanged]'''
+
* '''2011-12''' [http://btrfs.boxacle.net Btrfs Performance Analysis]
* '''2011-03 [http://www.phoronix.com/scan.php?page=article&item=btrfs_lzo_2638&num=1 Btrfs LZO Compression Performance]'''
+
* '''2011-11''' [http://www.phoronix.com/vr.php?view=16773 Testing The "Pretty Beefy" Btrfs Changes In Linux 3.2] (Phoronix.com)
* '''2010-12 [http://www.phoronix.com/scan.php?page=article&item=btrfs_space_cache&num=1 Benchmarks Of The Btrfs Space Cache Option]''' Comparing the performance of Btrfs using the default mount options, using the space_cache mount option, using the compress mount option for Btrfs file compression, and lastly using both the space_cache and compression mount options to benefit from the free space caching and Zlib compression.
+
* '''2011-10''' [http://www.ilsistemista.net/index.php/linux-a-unix/21-ext3-ext4-xfs-and-btrfs-filesystems-comparison-on-linux-kernel-300.html EXT3 vs EXT4 vs XFS vs BTRFS - filesystems comparison on Linux kernel 3.0.0] (Ilsistemista.net)
* '''2010 [http://www.mayrhofer.eu.org/ssd-linux-benchmark SSD Linux benchmarking: Comparing filesystems and encryption method]
+
* '''2011-09''' [http://www.phoronix.com/scan.php?page=article&item=btrfs_linux31_ssd&num=1 Testing EXT4 & Btrfs On A Serial ATA 3.0 SSD] (Phoronix.com)
* '''2010-11 [http://www.phoronix.com/scan.php?page=article&item=linux_2637_ext4btrfs&num=1 Phoronix: The Linux 2.6.37 Kernel With EXT4 & Btrfs]''' Comparison between Btrfs and Ext4.
+
* '''2011-05''' [http://www.phoronix.com/scan.php?page=article&item=linux_2639_fs&num=1 Linux 2.6.39: XFS Speeds-Up, EXT4 & Btrfs Unchanged] (Phoronix.com)
* '''2010-10 [http://www.linux-mag.com/id/7876 One Billion Files]''' Btrfs performs well in comparison to other filesystems, when there are a billion files in the filesystem.
+
* '''2011-03''' [http://www.phoronix.com/scan.php?page=article&item=btrfs_lzo_2638&num=1 Btrfs LZO Compression Performance] (Phoronix.com)
* '''2009-05 [http://www.phoronix.com/scan.php?page=article&item=btrfs_ssd_mode&num=1 Phoronix Test With SSD Mode]''' This test show that btrfs is slower with ssd option activated. Ssd code has been updated during 2.6.30-rc and is expected to be faster.
+
* '''2010-12''' [http://www.phoronix.com/scan.php?page=article&item=btrfs_space_cache&num=1 Benchmarks Of The Btrfs Space Cache Option] (Phoronix.com) Comparing the performance of Btrfs using the default mount options, using the space_cache mount option, using the compress mount option for Btrfs file compression, and lastly using both the space_cache and compression mount options to benefit from the free space caching and Zlib compression.
* '''2009-04 [http://www.phoronix.com/scan.php?page=article&item=btrfs_benchmarks&num=1 Phoronix Performance Test on Fedora 11 Preview]''' The phoronix workload is mostly CPU based, but they do have a few filesystem benchmarks. Btrfs performs well, but you can see the checksumming and metadata duplication show up on their single disk streaming write workload. dbench in general measures lots of different caching effects, and is not a great measure of everyday performance.
+
* '''2010''' [http://www.mayrhofer.eu.org/ssd-linux-benchmark SSD Linux benchmarking: Comparing filesystems and encryption method]
* '''2008-10 [http://btrfs.boxacle.net Btrfs performance analysis by Steven Pratt and IBM]''' The benchmarks from IBM demonstrate some bottlenecks we have in the extent recording on large workloads. We're working on fixes for these.
+
* '''2010-11''' [http://www.ilsistemista.net/index.php/linux-a-unix/6-linux-filesystems-benchmarked-ext3-vs-ext4-vs-xfs-vs-btrfs.html EXT3 vs EXT4 vs XFS vs BTRFS linux filesystems benchmark] (Ilsistemista.net)
* '''2008-04 [[Multi-device Benchmarks]]'''
+
* '''2010-11''' [http://www.phoronix.com/scan.php?page=article&item=linux_2637_ext4btrfs&num=1 Phoronix: The Linux 2.6.37 Kernel With EXT4 & Btrfs] (Phoronix.com) Comparison between Btrfs and Ext4.
 +
* '''2010-10''' [http://www.linux-mag.com/id/7876 One Billion Files] Btrfs performs well in comparison to other filesystems, when there are a billion files in the filesystem.
 +
* '''2009-05''' [http://www.phoronix.com/scan.php?page=article&item=btrfs_ssd_mode&num=1 Phoronix Test With SSD Mode] (Phoronix.com) This test show that btrfs is slower with ssd option activated. Ssd code has been updated during 2.6.30-rc and is expected to be faster.
 +
* '''2009-04''' [http://www.phoronix.com/scan.php?page=article&item=btrfs_benchmarks&num=1 Phoronix Performance Test on Fedora 11 Preview] (Phoronix.com) The phoronix workload is mostly CPU based, but they do have a few filesystem benchmarks. Btrfs performs well, but you can see the checksumming and metadata duplication show up on their single disk streaming write workload. dbench in general measures lots of different caching effects, and is not a great measure of everyday performance.
 +
* '''2008-10''' [http://btrfs.boxacle.net Btrfs performance analysis by Steven Pratt and IBM] The benchmarks from IBM demonstrate some bottlenecks we have in the extent recording on large workloads. We're working on fixes for these.
 +
* '''2008-04''' [[Multi-device Benchmarks]]

Revision as of 11:27, 19 February 2013

Btrfs is a new copy on write (CoW) filesystem for Linux aimed at implementing advanced features while focusing on fault tolerance, repair and easy administration. Jointly developed at Oracle, Red Hat, Fujitsu, Intel, SUSE, STRATO and many others, Btrfs is licensed under the GPL and open for contribution from anyone.

Btrfs is under heavy development, but every effort is being made to keep the filesystem stable and fast. Because of the speed of development, you should run the latest kernel you can (either the latest release kernel from kernel.org, or the latest -rc kernel. Please email the Btrfs mailing list if you have any problems or questions while using Btrfs.

Contents

Features

Linux has a wealth of filesystems from which to choose, 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.

The main Btrfs features available at the moment include:

  • Extent based file storage
  • 2^64 byte == 16 EiB maximum file size
  • Space-efficient packing of small files
  • Space-efficient indexed directories
  • Dynamic inode allocation
  • Writable snapshots, read-only snapshots
  • Subvolumes (separate internal filesystem roots)
  • Checksums on data and metadata (crc32c)
  • Compression (zlib and LZO)
  • Integrated multiple device support
    • File Striping, File Mirroring, and File Striping+Mirroring implementations
  • SSD (Flash storage) awareness (TRIM/Discard for reporting free blocks for reuse) and optimizations (e.g. avoiding unnecessary seek optimizations, sending writes in clusters, even if they are from unrelated files. This results in larger write operations and faster write throughput)
  • Efficient incremental backup
  • Background scrub process for finding and fixing errors on files with redundant copies
  • Online filesystem defragmentation
  • Offline filesystem check
  • Conversion of existing ext3/4 file systems
  • Seed devices. Create a (readonly) filesystem that acts as a template to seed other Btrfs filesystems. The original filesystem and devices are included as a readonly starting point for the new filesystem. Using copy on write, all modifications are stored on different devices; the original is unchanged.
  • Subvolume-aware quota support
  • Send/receive of subvolume changes
    • Efficient incremental filesystem mirroring

Additional features in development, or planned, include:

  • Very fast offline filesystem check
  • File Striping with Single and Dual Parity
  • Object-level mirroring and striping
  • Alternative checksum algorithms
  • Online filesystem check
  • Other compression methods (snappy, lz4)
  • Hot data tracking and moving to faster devices (currently being pushed as a generic feature available through VFS)

News

Coming in 3.8

  • ability to replace devices at runtime in an effective way (description)
  • speed improvements (cumulative effect of many small improvements)
  • a few more bugfixes

Linux in 3.7 (Dec 2012)

  • fsync speedups
  • removed limitation of number of hardlinks in a single directory
  • file hole punching (LWN article)
  • per-file NOCOW
  • fixes to send/receive

Enterprise btrfs support (Feb 2012)

  • Since February 2012 there are two vendors who support btrfs in their distributions, Oracle and SUSE.

Read about past releases in the Changelog

Articles, presentations, podcasts

Documentation

Guides and usage information

Project information

Using the built-in tools

  • btrfs — main administration tool
  • mkfs.btrfs — creating the filesystem
  • btrfsck — repairing file systems
  • restore and find-root — utilities to find and restore data from an unmountable filesystem
  • btrfs-convert — tool to convert in-place from ext2/3/4 filesystems to btrfs

Developer documentation

  • Code documentation — trees, source files, sample code for manipulating trees
  • Data Structures — detailed on-disk data structures
  • Trees — detailed in-tree representation of files and directories

Source code download

Benchmarking

Personal tools