HAMMER (file system)
| Developer(s) | Matthew Dillon |
|---|---|
| Full name | HAMMER |
| Introduced | July 21, 2008 with DragonFly BSD 2.0 |
| Structures | |
| Directory contents | Modified B+ tree |
| Limits | |
| Max volume size | 1 EiB |
| Features | |
| Forks | No |
| File system permissions | UNIX permissions |
| Transparent compression | Yes |
| Data deduplication | On 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. HAMMER also supports data block deduplication, meaning that identical data blocks will be stored only once on a file system. A successor, HAMMER2, was announced in 2011 and became the default in Dragonfly 5.2 (April 2018).