Dragonfly BSD and the Hammer Filesystem Aug 6, 2008, 07 :30 UTC (0 Talkback[s]) (4884 reads) (Other stories by Juliet Kemp)
"Hammer is a fine-grained snapshot filesystem designed for large disks/media. Its sweetspot begins at 500GB, and it can handle up to 1 Exabyte of data. Hammer runs a snapshot every every time the system syncs its mounts, in effect every 30-60 seconds. This history is retained and can easily be sifted through."