Btrfs introduction

Linux has a wealth of filesystems to choose from, 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 Btrfs disk format is not yet finalized, and it currently does not handle disk full conditions at all. Things are under heavy development, and Btrfs is not suitable for any uses other than benchmarking and review.

• Extent based file storage (2⁶⁴ max file size)
• Space efficient packing of small files
• Space efficient indexed directories
• Dynamic inode allocation
• Writable snapshots
• Subvolumes (separate internal filesystem roots)
• Object level mirroring and striping
• Checksums on data and metadata (multiple algorithms available)
• Strong integration with device mapper for multiple device support
• Online filesystem check
• Very fast offline filesystem check
• Efficient incremental backup and FS mirroring

Currently the code is in an early implementation phase. It is not optimized and many basic features still need to be added. However, Btrfs does perform well in a number of benchmarks, and it is ready for additional testing, review and analysis.

Btrfs has moved

The Btrfs pages have moved to http://btrfs.wiki.kernel.org, please visit the new site to find documentation, downloads and more details on Btrfs.