| Developer(s) | SUSE, Meta, Western Digital, Oracle Corporation, Fujitsu, Fusion-io, Intel, The Linux Foundation, Red Hat, and Strato AG[1] |
|---|---|
| Full name | B-tree file system |
| Introduced | March 23, 2009 with Linux kernel 2.6.29 |
| Partition IDs | |
| Structures | |
| Directory contents | B-tree |
| File allocation | Extents |
| Bad blocks | None recorded |
| Limits | |
| Max volume size | 16 EiB[3][a] |
| Max file size | 16 EiB[3][a] |
| Max no. of files | 264[b][4] |
| Max filename length | 255 ASCII characters (fewer for multibyte character encodings such as Unicode) |
| Allowed filename characters | All except '/' and NUL ('\0') |
| Features | |
| Dates recorded | Creation (otime),[5] modification (mtime), attribute modification (ctime), and access (atime) |
| Date range | 64-bit signed int offset from 1970-01-01T00:00:00Z[6] |
| Date resolution | Nanosecond |
| Attributes | POSIX and extended attributes |
| File system permissions | Unix permissions, POSIX ACLs |
| Transparent compression | Yes (zlib, LZO[7] and (since 4.14) ZSTD[8]) |
| Transparent encryption | Planned[9] |
| Data deduplication | Yes[10] |
| Copy-on-write | Yes |
| Other | |
| Supported operating systems | Linux, Windows,[11] ReactOS[12] |
| Website | docs |
Btrfs (pronounced as "better F S",[9] "butter F S",[13][14] "b-tree F S",[14] or B.T.R.F.S.) is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager (distinct from Linux's LVM), developed together. It was created by Chris Mason in 2007[15] for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel.[16]
Btrfs is intended to address the lack of pooling, snapshots, checksums, and integral multi-device spanning in Linux file systems.[9] 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".[17]
- ^ "Contributors at BTRFS documentation". kernel.org. 15 June 2022. Retrieved 5 December 2022.
- ^ "GPT fdisk - ArchWiki".
- ^ a b Cite error: The named reference
file-system-limitswas invoked but never defined (see the help page). - ^ Cite error: The named reference
btrfs-wiki-1was invoked but never defined (see the help page). - ^ Corbet, Jonathan (26 July 2010). "File creation times". LWN.net. Retrieved 15 August 2015.
- ^ "On-disk Format - btrfs Wiki". btrfs.wiki.kernel.org.
- ^ "btrfs Wiki". kernel.org. Retrieved 19 April 2015.
- ^ "Linux_4.14 - Linux Kernel Newbies". kernelnewbies.org.
- ^ a b c Cite error: The named reference
CM090622was invoked but never defined (see the help page). - ^ "Deduplication". kernel.org. Retrieved 19 April 2015.
- ^ "Windows Driver on GitHub.com". GitHub. Retrieved 10 January 2023.
- ^ "ReactOS 0.4.1 Released". reactos.org. Retrieved 11 August 2016.
- ^ "Oracle Linux 7 Q&A with Wim Coekaerts". Oracle. Event occurs at 1m 15s. Archived from the original on 18 August 2016. Retrieved 6 February 2016.
- ^ a b Henson, Valerie (31 January 2008). Chunkfs: Fast file system check and repair. Melbourne, Australia. Event occurs at 18m 49s. Retrieved 5 February 2008.
It's called Butter FS or B-tree FS, but all the cool kids say Butter FS
- ^ Salter, Jim (24 September 2021). "Examining btrfs, Linux's perpetually half-finished filesystem". Ars Technica. Retrieved 11 June 2023.
Chris Mason is the founding developer of btrfs, which he began working on in 2007 while working at Oracle. This leads many people to believe that btrfs is an Oracle project—it is not. The project belonged to Mason, not to his employer, and it remains a community project unencumbered by corporate ownership to this day.
- ^ "Linux kernel commit changing stability status in fs/btrfs/Kconfig". Retrieved 8 February 2019.
- ^ Kerner, Sean Michael (30 October 2008). "A Better File System for Linux?". InternetNews.com. Archived from the original on 8 April 2011. Retrieved 27 August 2020.
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