# Btrfs

> file system based on the copy-on-write principle using B-trees, developed at Oracle since 2007

**Wikidata**: [Q283820](https://www.wikidata.org/wiki/Q283820)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Btrfs)  
**Source**: https://4ort.xyz/entity/btrfs

## Summary
Btrfs is a file system based on the copy-on-write principle using B-trees, developed at Oracle starting in 2007. It provides advanced features like snapshots, compression, deduplication, and encryption for modern storage needs.

## Key Facts
- Btrfs was developed at Oracle starting in 2007 and first published in 2009
- It is licensed under the GNU General Public License
- Version 5.16 was released on January 10, 2022
- Btrfs supports operating systems including Linux, ReactOS, and Microsoft Windows
- Maximum file size in Btrfs is 16 exabytes
- Maximum disk partition size is 16 exabytes
- Maximum filename length is 255 characters
- It is a journaling file system and multi-device file system
- Developers include Oracle Corporation, Fujitsu, and Red Hat

## FAQs
### Q: What is Btrfs?
A: Btrfs is a file system based on the copy-on-write principle using B-trees. It provides advanced features like snapshots, compression, deduplication, and encryption for modern storage needs.

### Q: When was Btrfs developed and by whom?
A: Btrfs was developed at Oracle starting in 2007 and first published in 2009. Development has involved Oracle Corporation, Fujitsu, and Red Hat.

### Q: What operating systems support Btrfs?
A: Btrfs is supported on Linux, ReactOS, and Microsoft Windows. It was primarily designed for Linux systems but has been adapted for other platforms.

### Q: What are the main features of Btrfs?
A: Btrfs offers filesystem-level encryption, data deduplication, compression, and copy-on-write functionality. It also supports snapshots, which allow for point-in-time data backup and versioning.

### Q: What is the maximum size of files and partitions in Btrfs?
A: Btrfs supports files up to 16 exabytes in size and disk partitions up to 16 exabytes. The maximum filename length is 255 characters.

## Why It Matters
Btrfs addresses the growing need for reliable, feature-rich file systems in modern computing environments. Its copy-on-write architecture provides data integrity and allows for efficient snapshots, making it valuable for backup systems and virtualization. As storage capacities have grown exponentially, Btrfs's ability to handle exabyte-scale filesystems with features like compression and deduplication helps optimize storage utilization. The filesystem's multi-device support enables flexible storage configurations across multiple physical devices, providing both redundancy and scalability. These features make Btrfs particularly important for server environments, high-performance computing, and systems requiring robust data protection mechanisms.

## Notable For
- Implementation of copy-on-write principle using B-trees for efficient storage and data integrity
- Built-in support for filesystem-level encryption, data deduplication, and compression
- Multi-device file system capabilities enabling flexible storage configurations
- Journaling architecture for faster recovery after system crashes
- Advanced snapshot functionality for point-in-time data backup and versioning

## Body
### Overview
Btrfs is a modern file system designed for high-capacity storage systems. It implements a copy-on-write (CoW) architecture using B-trees as its core data structure, which ensures data integrity and enables efficient storage operations.

### Development History
Btrfs was developed at Oracle starting in 2007 and was first published in 2009. The project has seen contributions from multiple organizations, including Oracle Corporation (the original developer), Fujitsu, and Red Hat. Version 5.16, released on January 10, 2022, represents a stable release of the filesystem.

### Technical Architecture
At its core, Btrfs uses B-trees for data organization and implements the copy-on-write principle. This approach ensures that data is never overwritten in place; instead, modified data is written to new locations, and references to the old data are updated. This mechanism provides inherent data integrity and enables efficient snapshot creation.

### Features
Btrfs offers several advanced features:
- Filesystem-level encryption
- Data deduplication
- Compression
- Snapshots
- Subvolumes
- RAID-like capabilities for data redundancy
- Checksums for data integrity verification

### Supported Platforms
Btrfs primarily supports Linux operating systems. It has also been adapted for ReactOS and Microsoft Windows, though its full feature set is most commonly available on Linux systems.

### Version History
Btrfs has evolved through numerous versions since its initial release in 2009. Version 5.16, released on January 10, 2022, represents a stable milestone in the filesystem's development history.

### Filesystem Properties
Btrfs supports:
- Files up to 16 exabytes in size
- Disk partitions up to 16 exabytes
- Filenames up to 255 characters in length
- Various partition type identifiers including 0FC63DAF-8483-4772-8E79-3D69D8477DE4 (GUID Partition Table) and 0x83 (Master Boot Record)

## Schema Markup
```json
{
  "@context": "https://schema.org",
  "@type": "Thing",
  "name": "Btrfs",
  "description": "A file system based on the copy-on-write principle using B-trees, developed at Oracle since 2007",
  "url": "https://btrfs.readthedocs.io/",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q15241312",
    "https://en.wikipedia.org/wiki/Btrfs"
  ],
  "additionalType": "File system",
  "license": "GNU General Public License",
  "version": "5.16",
  "datePublished": "2009-03-00",
  "developer": [
    "Oracle Corporation",
    "Fujitsu",
    "Red Hat"
  ],
  "operatingSystem": [
    "Linux",
    "ReactOS",
    "Microsoft Windows"
  ],
  "hasPart": "Copy-on-write mechanism",
  "hasProperty": [
    "Filesystem-level encryption",
    "Data deduplication",
    "Filesystem-level compression",
    "Snapshots",
    "B-tree data structure"
  ],
  "storageCapacity": {
    "@type": "QuantitativeValue",
    "value": 16,
    "unitCode": "EB"
  },
  "maximumFileSize": {
    "@type": "QuantitativeValue",
    "value": 16,
    "unitCode": "EB"
  },
  "maximumFileNameLength": {
    "@type": "QuantitativeValue",
    "value": 255,
    "unitCode": "character"
  }
}

## References

1. [Source](http://thread.gmane.org/gmane.comp.file-systems.btrfs/34607)
2. [2022](https://github.com/kdave/btrfs-devel/releases/tag/v5.16)
3. Freebase Data Dumps. 2013
4. Quora