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HAMMER2 is a successor to the HAMMER filesystem, redesigned from the ground up to support enhanced clustering. HAMMER2 supports online and batched deduplication, snapshots, directory entry indexing, multiple mountable filesystem roots, mountable snapshots, a low memory footprint,
The HAMMER2 file system was conceived by Matthew Dillon, who initially planned to bring it up to minimal working state by July 2012 and ship the final version in 2013. During Google Summer of Code 2013 Daniel Flores implemented
compression
Compression may refer to:
Physical science
*Compression (physics), size reduction due to forces
*Compression member, a structural element such as a column
*Compressibility, susceptibility to compression
* Gas compression
*Compression ratio, of a ...
, encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can de ...
, zero-detection, data and metadata checksum
A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data ...
ming, and synchronization to other filesystems or nodes.
History
The HAMMER2 file system was conceived by Matthew Dillon, who initially planned to bring it up to minimal working state by July 2012 and ship the final version in 2013. During Google Summer of Code 2013 Daniel Flores implemented compression
Compression may refer to:
Physical science
*Compression (physics), size reduction due to forces
*Compression member, a structural element such as a column
*Compressibility, susceptibility to compression
* Gas compression
*Compression ratio, of a ...
in HAMMER2 using LZ4 and zlib
zlib ( or "zeta-lib", ) is a software library used for data compression. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. zlib is also ...
algorithms. On June 4, 2014, DragonFly 3.8.0 was released featuring support for HAMMER2, although the file system was said to be not ready for use. On October 16, 2017, DragonFly 5.0 was released with bootable
In computing, booting is the process of starting a computer as initiated via hardware such as a button or by a software command. After it is switched on, a computer's central processing unit (CPU) has no software in its main memory, so some ...
support for HAMMER2, though file-system status was marked as experimental.
HAMMER2 had a long incubation and development period before it officially entered production in April 2018, as the recommended root filesystem in the Dragonfly BSD 5.2 release.
Dillon continues to actively develop and maintain HAMMER2 as of June 2020.
See also
*Comparison of file systems
The following tables compare general and technical information for a number of file systems.
General information
Limits
Metadata
Features File capabilities
Block capabilities
Note that in addition to the below table, blo ...
* List of file systems
The following lists identify, characterize, and link to more thorough information on Computer file systems.
Many older operating systems support only their one "native" file system, which does not bear any name apart from the name of the operating ...
* ZFS
ZFS (previously: Zettabyte File System) is a file system with volume management capabilities. It began as part of the Sun Microsystems Solaris operating system in 2001. Large parts of Solaris – including ZFS – were published under an ope ...
* Btrfs
Btrfs (pronounced as "better F S", "butter F S", "b-tree F S", or simply by spelling it out) is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager (not to be confused ...
* OpenZFS
OpenZFS is a free and open-source storage platform licensed under CDDL that encompasses the functionality of traditional filesystems and logical volume manager. It includes protection against data corruption, support for high storage capaciti ...
References
External links
* {{File systems , state=expanded DragonFly BSD Distributed file systems 2014 software