HAMMER (file system)

HAMMER
Developer(s)Matthew Dillon
Full nameHAMMER
IntroducedJuly 21, 2008; 16 years ago (2008-07-21) with DragonFly BSD 2.0[1][2]
Structures
Directory contentsModified B+ tree[3]
Limits
Max volume size1 EiB[3]
Features
ForksNo
File system
permissions
UNIX permissions
Transparent
compression
Yes[4]
Data deduplicationOn demand
Other
Supported
operating systems
DragonFly BSD

HAMMER is a high-availability 64-bit file system developed by Matthew Dillon for DragonFly BSD using B+ trees. Its major features include infinite NFS-exportable snapshots, master–multislave operation, configurable history retention, fsckless-mount, and checksums to deal with data corruption.[5] HAMMER also supports data block deduplication, meaning that identical data blocks will be stored only once on a file system.[6] A successor, HAMMER2, was announced in 2011 and became the default in Dragonfly 5.2 (April 2018).[7]

  1. ^ Cite error: The named reference lor-2007 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference phoronix was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference hammer-design-doc was invoked but never defined (see the help page).
  4. ^ "HAMMER2 File-System Now Uses LZ4 Compression By Default - Phoronix". www.phoronix.com.
  5. ^ Cite error: The named reference man-5-hammer was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference dedup-devblog was invoked but never defined (see the help page).
  7. ^ Dillon, Matthew (11 May 2011). "HAMMER2 announcement". users (Mailing list).