Btrfs
| Developer(s) | SUSE, Meta, Western Digital, Oracle Corporation, Fujitsu, Fusion-io, Intel, The Linux Foundation, Red Hat, and Strato AG |
|---|---|
| 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 |
| Max file size | 16 EiB |
| Max no. of files | 264 |
| 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), modification (mtime), attribute modification (ctime), and access (atime) |
| Date range | 64-bit signed int offset from 1970-01-01T00:00:00Z |
| Date resolution | Nanosecond |
| Attributes | POSIX and extended attributes |
| File system permissions | Unix permissions, POSIX ACLs |
| Transparent compression | Yes (zlib, LZO and (since 4.14) ZSTD) |
| Transparent encryption | Planned |
| Data deduplication | Yes |
| Copy-on-write | Yes |
| Other | |
| Supported operating systems | Linux, Windows, ReactOS |
| Website | btrfs |
Btrfs (pronounced as "better F S", "butter F S", "b-tree F S", 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 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel.
Btrfs is intended to address the lack of pooling, snapshots, integrity checking, data scrubbing, and integral multi-device spanning in Linux file systems. 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".