HAMMER2 File-System Picks Up Live Deduplication Support

Just a few days ago I was writing about DragonFlyBSD's HAMMER2 file-system maturing and now this weekend it's picked up another high profile feature: live deduplication.

HAMMER2 will now attempt to deduplicate the file-system in real-time. DragonFlyBSD lead developer Matthew Dillon explained, "First attempt at a live dedup. The H2 strategy code now caches {data_off, crc} info to track recently accessed data blocks. The cache is checked in the strategy_write code after device-level block encoding. If we get a cache hit, the disk block is compared against the write data and reused if it matches."

This live deduplication is aimed to catch cp/cpdup-type copies of files while a bulk dedup feature is also being tackled.

More details via this Git commit from this morning that added in the live deduplication for this next-generation HAMMER file-system.